Karetu was born in Hastings and grew up in Waikaremoana, a Māori speaking community with which his mother was affiliated. He attended Kōkako Native School, Huiarau Native School, Waimarama Native School and later Wellington College, where he was a boarder for five years. Karetu spent two years at Wellington Teachers’ Training College where he led the Māori Club; he was awarded a third year’s study at Victoria University. Karetu graduated with a B.A. degree in French, German and Māori and in 1960 taught at Taumarunui High School. In December 1961 he went to London where he assumed the position of Information Officer for the New Zealand High Commission (Feb. 1962). He returned to New Zealand in 1969 to take up a teaching position at Fairfield College in Hamilton and one year later began a part-time lectureship in Māori language teaching at the University of Waikato. In 1972 he was appointed senior lecturer and in 1976 became Reader (Associate Professor) and Head of the Department of what was later to become the Centre for Māori Studies and Research. In 1987 Karetu was appointed Foundation Professor of Māori, a position he held until June 1992. From August 1987 he was on leave from Waikato University working in the establishment of the Māori Language Commission. In 1992 he was appointed Māori Language Commissioner, replacing Sir Kingi Ihaka who resigned in January 1992 for health reasons. Karetu is chair of Kohanga Reo in New Zealand and chair of Aotearoa Traditional Māori Performing Arts Festival. He is CEO of Mitai Tours. He is a former professor at the University of Hawaii.
- Interview and correspondence with Timoti Karetu 10 Aug. 1992, and 4 Sep. 1998.
- http://www.polynesia.com/press/press_03.10.04_whakataetae.html 3 July 2008.
- "Shame be His Punishment." Te Wharekura 5. No further details.
- Short story in Māori.
- Te Wharekura 9. No further details.
- Non-fiction article.
- Nga Waiata me Nga Haka a te Kapa Haka o Te Whare Wananga o Waikato. Comp. Timoti S. Karetu. [Hamilton, N.Z.]: U of Waikato, revised ed. 1987. Rev.ed. 1992.
- A collection of the waiata and haka performed by the Māori culture group at Waikato University.
- "Kia U, Kia Mau Ki To Māoritanga." Te Ao Hou 49 (1964): 18-19.
- "Māori Gathering in London." Te Ao Hou 50 (1965): 7.
- An account of a reception held at New Zealand House, London, on 27 November 1964 when the High Commissioner, Sir Thomas Macdonald, and Lady Macdonald introduced Canon and Mrs Rangiihu to the Māori community of London.
- "Kati Au Ka Hoki Ki Taku Whenua Tupu." Te Ao Hou 59 (1967): 9-10.
- "Cities, and the Future of Māoridom." Te Māori: The Official Journal of the New Zealand Māori Council 1.4 (1970): 17-19.
- Co-authors Dane Archer, Timoti S. Karetu and Roger S. Oppenheim.The authors examine the impact of the increased urbanisation of Māoridom on Māori children. They publish the results of a study they conducted on urban and rural Māori school children to ascertain which group was more conversant with ‘specifically "Māori" information’. The article concludes with options for urban-dwelling Māori parents who want to inculcate in their children a knowledge of their taha Māori.
- "Intelligence and Pakeha Child." National Education: The Journal of the NZ Educational Institute 53.577 (1971): 258-260.
- A satirical article discussing an intelligence test called MOTIS which was devised by Dane Archer, Roger S. Oppenheim, T. Sam Karetu and Ross St. George. Unlike the OTIS test which the authors state was developed in foreign cultures, MOTIS utilises solely ‘New Zealand-based’ material. The MOTIS intelligence test was given to 113 Māori and Pakeha third and fourth formers; the authors write that the results demonstrated that Māori students scored higher than the Pakeha students.
- "Ka Tangi Hoki Ko Au." Te Ao Hou 69 (1971?): 8-10.
- "Ka Mahora Ki te Riu Ki Waikato ‘He Powhiri’/Stretched Out in the Waikato Valley ‘An Invitation’." Te Ao Hou 73 (1973): 4-10. In Māori and English.
- Karetu pays tribute to the people of the Waikato on the occasion of the seventh annual celebration of the coronation of Te Ariki Tapairu, Dame Te Atairangikaahu. Karetu writes how the Waikato people worked tirelessly under the leadership of Te Puea to reclaim confiscated land and establish Turangawaewae Marae with its impressive houses. At this celebration the foundation stone for the new Kimikimi dining room was laid.
- "Language and Protocol of the Marae." Te Ao Hurihuri: The World Moves On. Ed. Michael King. Wellington, N.Z.: Hicks Smith & Sons, 1975. 35-54. Rpt. in Te Ao Hurihuri: Aspects of Māoritanga. Auckland, N.Z.: Reed, 1992. 28-41.
- Karetu gives a rich account of the wealth and beauty of Māori oral literature and illustrates the various aspects of oral literature that are practised in formal marae protocol.
- "Kawa in Crisis." Tihe Mauriora: Aspects of Māoritanga. Ed. Michael King. [Wellington, N.Z.]: Methuen, 1978. 67-79.
- Karetu writes of different tribal responses to kawa in contemporary society. He notes that the value of kawa is that ‘it makes behaviour simple and clear cut’. He mourns the fact that kawa is ‘being sacrificed in the name of convenience’ on the marae. He discusses the speaking of te reo Māori on the marae.
- "Taku Taha Māori: My Māoriness." He Mātāpuna: A Source: Some Māori Perspectives. Wellington, N.Z.: Te Kaunihera Whakakaupapa mō Aotearoa, New Zealand Planning Council NZPC No. 14, Dec 1979. [Rpt. in 1989.] 27-31.
- Karetu describes his Tuhoe tribal roots and discusses his upbringing as a whangai and as a fluent Māori speaker raised in the home of his grandparents. Karetu speaks of the significant people in his development - Beth Ranapia and John Rangihau.
- "Te reo Māori." New Zealand Official Yearbook. 1988. 217-227.
- Written with Jeffrey Waite
- "Background Versus Blood Quantum." 1840-1990: A Long White Cloud? Essays for1990. Ed. Tom Newnham. Auckland, N.Z.: Graphic Publications in association with Citizens’ Association for Racial Equality, 1989. 97-101.
- Karetu describes the two communities he grew up in (Waikaremoana and Waimarama) and discusses the question of Māori identity. Karetu writes that ‘[d]espite the more than 200 years of contact... racial harmony continues to be elusive’. He maintains ‘that it will remain so while no acknowledgement is made of [the Māori] right to be different, to speak our own language where and when we like, to celebrate life in out own way on our own terms and to be in control of our destiny.’
- "Toku Mapihi Maurea o Tuawhakarere: Māori Language and Culture." Te Reo o Te Tiriti Mai Rano: The Treaty Is Always Speaking. Ed. Bernard Kernot. Wellington, N.Z.: Tertiary Christian Studies Programme of the Combined Chaplaincies, Victoria University of Wellington, N.Z., 1989. 70-78.
- Karetu writes of the many obstacles in New Zealand history and society facing the recognition and survival of the Māori language. He notes that despite the clear capacity of the Māori language to encompass change and adapt, educational policies since the 1860s have reflected the supremacy of English at the expense of Māori. He urges fluent Māori speakers to use the language in all appropriate situations. He expresses his astonishment at the Māori societies that still persist in using English as their main medium of communication.
- "The Māori Language Today." Puna Wairere: Essays by Māori. Wellington, N.Z.: New Zealand Planning Council/Te Kaunihera Whakakaupapa mo Aotearoa, 1990. 55-60.
- Karetu writes of the overt and covert opposition to the official use of te reo Māori in New Zealand. While he argues against making te reo Māori a compulsory subject in school curriculum, he argues that the language should be made available to ‘those who so desire it’. He also states that there needs to be ‘a greater tolerance of the right of things Māori to exist, to be nurtured and to grow’.
- "Tōku Reo, Tōku Mana." New Settlers and Multicultural Education Issues 7.3 (1990): 15-19. Rpt. in Te Ao Mārama: Regaining Aotearoa: Māori Writers Speak Out. Comp. and ed. Witi Ihimaera. Contributing ed. Haare Williams, Irihapeti Ramsden and D. S. Long. Vol. 2: He Whakaatanga O Te Ao: The Reality. Auckland, N.Z.: Reed, 1993. 222-229.
- An examination of the survival of the Māori language over the last 150 years. Karetu writes that within Māoridom, te reo Māori is not simply a tool of communication but is also a symbol of mana and identity. Karetu disfavours the use of the term ‘Renaissance’ in relation to the new resurgence of Māori language and culture and states instead that it is simply a more ‘aggressive and assertive approach on the part of the Māori regarding the retention of the language and culture’. In conclusion he argues that the promotion of the Māori language must be actively pursued in the 1990s.
- "How Can the Māori Language Survive?" Te Karanga 6.3 (1990): 19.
- "The Clue to Identity." New Zealand Geographic 5 (1990): 112-117.
- Karetu describes the various traditional ways of establishing turangawaewae: through the placing of the placenta on specific land, through the concept of ahi ka (of keeping the fires burning for at least three generations), and through whakapapa. Karetu talks of urbanised Māori and whangai children who have been separated from their turangawaewae; he also describes the area of his own turangawaewae at Waikaremoana, Ruatahuna and Waimarama. He concludes by noting the place of language in establishing one’s turangawaewae; he also discusses physical and linguistic turangawaewae.
- "Te Ngahurutanga: A Decade of Protest, 1980-1990." Dirty Silence: Aspects of Language and Literature in New Zealand: Essays Arising From The University of Waikato Winter Lecture Series of 1990. Ed. Graham McGregor and Mark Williams. Associate editor Ray Harlow. Auckland, N.Z.: Oxford UP, 1991. 159-176.
- A comprehensive account of the content and sentiments expressed in haka composed from 1980-1990. The article includes the Māori text and English translation of various haka. Karetu writes that the ‘decade 1980-1990 has been one of the most active in terms of protest against the government and its policies. It has also been a decade of prolific composition of haka, waiata, and waiata-a-ringa of protest, thus continuing a long tradition.’
- Haka! Te Tohu O Te Whenua Rangātira: The Dance of a Noble People. Auckland, N.Z.: Reed, 1992.
- In this comprehensive nine-chapter publication Karetu examines the haka in Māori myths and tribal histories. He also discusses definitions of haka and provides early accounts of the haka. He describes the various types and themes of haka, examines Te Rauparaha’s ngeri Ka Mate and asks different Māori leaders their view of contemporary haka. He concludes by discussing issues concerning the future of the haka and the haka in the Aotearoa Māori Performing Arts Festivals. He includes a bibliography.
- He Maramatanga: Teachers’ Manual for Māori Language Text Books. [T. S. Karetu] Wellington, N.Z.: School Publications Branch, Department of education, 1974.
- Te Reo Rangātira. Wellington, N.Z.: Government Printer, iv, 1974.
- Te Reo Rangātira: A Course in Māori for Sixth and Seventh Forms. Wellington, N.Z.: Government Printer, 1984.
- Concise Māori Dictionary: Māori-English. Comp. A. W. Reed. Revised by T. S. Karetu. Wellington, N.Z.: Reed, 1984.
- Brougham, A. E. and A. W. Reed. Māori Proverbs. Revised by T. S. Karetu. Auckland, N.Z.: Heinemann Reed, 1987.
- "Te Tumu o Tainui/The Mooring Post of Tainui." The Penguin Book of Contemporary New Zealand Poetry/ Ngā Kupu T˚tohu o Aotearoa. Ed. Miriama Evans, Harvey McQueen and Ian Wedde. Auckland, N.Z.: Penguin, 1989. 266-267.
- Written in Māori with English translation
A tribute to the hospitality of the Tainui people on the opening of Tahua-roa.
- "Te Ao Pakeha." White Feathers: An Anthology of New Zealand and Pacific Island Poetry on the Theme of Peace. Ed. Terry Locke, Peter Low and John Winslade. Christchurch, N.Z.: Hazard, 1991. 61-62. Rpt. in Te Ao Mārama: Contemporary Māori Writing. Comp. and ed. Witi Ihimaera. Contributing ed. Haare Williams, Irihapeti Ramsden and D. S. Long. Vol. 5: Te Torino: The Spiral. Auckland, N.Z.: Reed, 1996. 210-211.
- "He Aha Te Hua O Te Taikaha?" White Feathers: An Anthology of New Zealand and Pacific Island Poetry on the Theme of Peace. Ed. Terry Locke, Peter Low and John Winslade. Christchurch, N.Z.: Hazard, 1991. 61-62. Rpt. in Te Ao Mārama: Contemporary Māori Writing. Comp. and ed. Witi Ihimaera. Contributing ed. Haare Williams, Irihapeti Ramsden and D. S. Long. Vol. 5: Te Torino: The Spiral. Auckland, N.Z.: Reed, 1996. 120.
- "He Aha Rā Kei te Tau o Taku Ate?" Te Ao Mārama: Contemporary Māori Writing. Comp. and ed. Witi Ihimaera. Contributing ed. Haare Williams, Irihapeti Ramsden and D. S. Long. Vol. 5: Te Torino: The Spiral. Auckland, N.Z.: Reed, 1996. 208-209.
- "E Noho Ana Rā i Tōku Taumata." Te Ao Mārama: Contemporary Māori Writing. Comp. and ed. Witi Ihimaera. Contributing ed. Haare Williams, Irihapeti Ramsden and D. S. Long. Vol. 5: Te Torino: The Spiral. Auckland, N.Z.: Reed, 1996. 209-210.
- "Te Kuika Māori." Te Ao Mārama: Contemporary Māori Writing. Comp. and ed. Witi Ihimaera. Contributing ed. Haare Williams, Irihapeti Ramsden and D. S. Long. Vol. 5: Te Torino: The Spiral. Auckland, N.Z.: Reed, 1996. 211-212.
- Rev. of Man of the Mist by Elsdon Craig. Te Ao Hou 51 (1965): 57.
- Rev. of Let’s Learn Māori by Bruce Biggs. Journal of the Polynesian Society 78.3 (1969): 439-440.
- Rev. of Whakatōhea of Ōpōtiki, by A. C. Lyall. Te Kaea: The Māori Magazine 1 (1979): 24.
- Rev. of Traditional Songs of the Māori, by Mervyn McLean and Margaret Orbell. Te Kaea: The Māori Magazine 1 (1979): 24-25.
- "Living On" in ‘The Poems of the 80s’" Rev. of The Penguin Book of Contemporary New Zealand Poetry/ Nga Kupu T˚tohu O Aotearoa, ed. by Miriama Evans, Harvey MncQueen and Ian Wedde. Listener 20 Nov. 1989: 111-112.
- There are two parts to this review of The Penguin Book of Contemporary New Zealand Poetry/ Nga Kupu T˚tohu O Aotearoa: In "1: A Fair Go" Elizabeth Caffin reviews the English language material; in "2: Living On" Timoti S Karetu reviews the Māori content.
- Rev. of In and Out of Touch: Whakamaa in Cross Cultural Context, by Joan Metge. Pacific Studies 13.1 (1990): 164-166.
- "How can the Māori Language Survive?" Te Karanga 6.3 (1990): 19.
- In this ngeri Karetu bewails the diminishing survival of the Māori language and urges Māori to speak it actively rather than leaving it to the kohanga reo or bilingual schools. Karetu wrote this ngeri in Māori with an English translation for the Te Whare Wananga o Waikato, the cultural group of Waikato University.
- Clark, Charlton. "The Hawaiian Experience a Sobering One for Waikato Lecturer." Tu Tangata 14 (1983): 42-43.
- After a year’s sabbatical leave which included time in Hawaii examining Hawaiian music and dance, Timoti Karetu comments on the decline in numbers of native Hawaiian speakers in Hawaii. In response, he argues that Māori need to maintain their language and not to expect it to survive merely through cultural groups. Karetu also comments on his visit to a Navajo language school in Arizona, and discusses his attendance at the Indigenous People’s Theatre Association Conference in Toronto.
- Ewing, Barbara. "Timoti Samuel Karetu." Te Ao Hou 59 (1967): 8.
- McLeod, Marion. "Let the Language Live." Listener 23 July 1990: 27.
- "Whare Wananga: Te reo is the Bottom Line." Tu Tangata 33 (1986/ 87): 26.
- A short discussion with Timoti Karetu, who was, at the time, the tutor of the Whare Wananga o Waikato who were runners-up in the Polynesian Festival in 1986 in Christchurch.
- Benton, Richard A. Materials for Teaching and Learning the Māori Language: A Bibliography of Published Materials for Teaching Māori to Speakers of Other Languages Compiled and Annotated by Richard A. Benton. Wellington, N.Z.: New Zealand Council for Educational Research, Māori Unit, 1979. 10.