Va estudiar Dret i més tard Filosofia a la Universitat de Monash, a Melbourne, on va llicenciar-se el 1969. Posteriorment va marxar a la Universitat d'Oxford, on va prendre contacte amb l'utilitarisme ètic mitjançant la lectura d'autors a llengua anglesa, com Jeremy Bentham i John Stuart Mill. Allà va participar en protestes contra la guerra del Vietnam, i també té lloc la seva «conversió» al vegetarianisme, per influència d'alguns estudiants, que li van despertar l'interès per l'ètica aplicada als animals. Després de finalitzar els seus estudis a Oxford el 1971, va romandre dos anys com a lector abans de marxar a la Universitat de Nova York com a professor assistent visitant.
A partir d'aquell moment inicia el seu camí cap a una renovació de l'ètica pràctica, aplicada sobretot a l'àmbit de la relació humana amb la vida (bioètica), fins que el 1975 publica la seva obra més famosa, Animal Liberation (Alliberament Animal). En ella proposa una ètica que, partint de l'home, es dirigeixi també cap a la resta dels animals, atacant el que ell anomena "especisme" o creença en la superioritat d'una espècie (en aquest cas l'ésser humà) sobre la resta. L'ètica pràctica de Singer inclou temes polèmics, com ara advocar per un tracte ètic als animals, l'avortament, l'eutanàsia, la pobresa i la distribució d'ingressos.
El mateix any de la publicació d'Animal Liberation va tornar a Melbourne, la seva ciutat natal, on va ensenyar més de dues dècades a la Universitat de La Trobe (1975-76) i Monash (1977-99). El 1999 va tornar als Estats Units per treballar com a professor de bioètica a la Universitat de Princeton. Des del 2005 ha compartit aquesta tasca amb la de professor a la Universitat de Melbourne.
Basant-se en una argumentació utilitarista, defèn l'avortament induït, matar nounats que presenten discapacitats severes i que els animals no humans no haurien de tenir drets bàsics diferents dels dels humans.[2]
Democracy and Disobedience, Clarendon Press, Oxford, 1973; Oxford University Press, New York, 1974; Gregg Revivals, Aldershot, Hampshire, 1994
Animal Liberation: A New Ethics for our Treatment of Animals, New York Review/Random House, New York, 1975; Cape, London, 1976; Avon, New York, 1977; Paladin, London, 1977; Thorsons, London, 1983. Harper Perennial Modern Classics, New York, 2009.
Animal Rights and Human Obligations: An Anthology (co-editor with Thomas Regan), Prentice-Hall, New Jersey, 1976. 2nd revised edition, Prentice-Hall, New Jersey, 1989
Marx, Oxford University Press, Oxford, 1980; Hill & Wang, New York, 1980; reissued as Marx: A Very Short Introduction, Oxford University Press, 2000; also included in full in K. Thomas (ed.), Great Political Thinkers: Machiavelli, Hobbes, Mill and Marx, Oxford University Press, Oxford, 1992
Animal Factories (co-author with James Mason), Crown, New York, 1980
The Expanding Circle: Ethics and Sociobiology, Farrar, Straus and Giroux, New York, 1981; Oxford University Press, Oxford, 1981; New American Library, New York, 1982. ISBN 0-19-283038-4
Hegel, Oxford University Press, Oxford i Nova York, 1982; reissued as Hegel: A Very Short Introduction, Oxford University Press, 2001; also included in full in German Philosophers: Kant, Hegel, Schopenhauer, Nietzsche, Oxford University Press, Oxford, 1997
Test-Tube Babies: a guide to moral questions, present techniques, and future possibilities (co-edited with William Walters), Oxford University Press, Melbourne, 1982
The Reproduction Revolution: New Ways of Making Babies (co-author with Deane Wells), Oxford University Press, Oxford, 1984. revised American edition, Making Babies, Scribner's New York, 1985
Should the Baby Live? The Problem of Handicapped Infants (co-author with Helga Kuhse), Oxford University Press, Oxford, 1985; Oxford University Press, New York, 1986; Gregg Revivals, Aldershot, Hampshire, 1994. ISBN 0-19-217745-1
In Defence of Animals (ed.), Blackwells, Oxford, 1985; Harper & Row, New York, 1986. ISBN 0-631-13897-8
Ethical and Legal Issues in Guardianship Options for Intellectually Disadvantaged People (co-author with Terry Carney), Human Rights Commission Monograph Series, no. 2, Australian Government Publishing Service, Canberra, 1986
Applied Ethics (ed.), Oxford University Press, Oxford, 1986
Animal Liberation: A Graphic Guide (co-author with Lori Gruen), Camden Press, London, 1987
Embryo Experimentation (co-editor with Helga Kuhse, Stephen Buckle, Karen Dawson and Pascal Kasimba), Cambridge University Press, Cambridge, 1990; paperback edition, updated, 1993
A Companion to Ethics (ed.), Basil Blackwell, Oxford, 1991; paperback edition, 1993
Save the Animals! (Australian edition, co-author with Barbara Dover and Ingrid Newkirk), Collins Angus & Robertson, North Ryde, NSW, 1991
The Great Ape Project: Equality Beyond Humanity (co-editor with Paola Cavalieri), Fourth Estate, London, 1993; hardback, St Martin's Press, New York, 1994; paperback, St Martin's Press, New York, 1995
How Are We to Live? Ethics in an Age of Self-interest, Text Publishing, Melbourne, 1993; Mandarin, London, 1995; Prometheus, Buffalo, NY, 1995; Oxford University Press, Oxford, 1997
Ethics (ed.), Oxford University Press, Oxford, 1994
Individuals, Humans and Persons: Questions of Life and Death (co-author with Helga Kuhse), Academia Verlag, Sankt Augustin, Germany, 1994.
Rethinking Life and Death: The Collapse of Our Traditional Ethics, Text Publishing, Melbourne, 1994; St Martin's Press, New York, 1995; reprint 2008. ISBN 0-312-11880-5 Oxford University Press, Oxford, 1995
The Greens (co-author with Bob Brown), Text Publishing, Melbourne, 1996
The Allocation of Health Care Resources: An Ethical Evaluation of the "QALY" Approach (co-author with John McKie, Jeff Richardson and Helga Kuhse), Ashgate/Dartmouth, Aldershot, 1998
A Companion to Bioethics (co-editor with Helga Kuhse), Blackwell, Oxford, 1998
Ethics into Action: Henry Spira and the Animal Rights Movement, Rowman and Littlefield, Lanham, Maryland, 1998; Melbourne University Press, Melbourne, 1999
Bioethics. An Anthology (co-editor with Helga Kuhse), Blackwell, 1999/ Oxford, 2006
A Darwinian Left, Weidenfeld and Nicolson, London, 1999; Yale University Press, New Haven, 2000. ISBN 0-300-08323-8
Writings on an Ethical Life, Ecco, New York, 2000; Fourth Estate, London, 2001. ISBN 0-06-019838-9
Unsanctifying Human Life: Essays on Ethics (edited by Helga Kuhse), Blackwell, Oxford, 2001
One World: The Ethics of Globalization, Yale University Press, New Haven, 2002; Text Publishing, Melbourne, 2002; 2nd edition, pb, Yale University Press, 2004; Oxford Longman, Hyderabad, 2004. ISBN 0-300-09686-0
Pushing Time Away: My Grandfather and the Tragedy of Jewish Vienna, Ecco Press, New York, 2003; HarperCollins Australia, Melbourne, 2003; Granta, London, 2004
The President of Good and Evil: The Ethics of George W. Bush, Dutton, New York, 2004; Granta, London, 2004; Text, Melbourne, 2004. ISBN 0-525-94813-9
How Ethical is Australia? An Examination of Australia's Record as a Global Citizen (with Tom Gregg), Black Inc, Melbourne, 2004
The Moral of the Story: An Anthology of Ethics Through Literature (co-edited with Renata Singer), Blackwell, Oxford, 2005
In Defense of Animals. The Second Wave (ed.), Blackwell, Oxford, 2005
The Way We Eat: Why Our Food Choices Matter, Rodale, New York, 2006 (co-author with Jim Mason); Text, Melbourne; Random House, London. Auudio version: Playaway. ISBN 1-57954-889-X
Eating (co-authored with Jim Mason), Arrow, London, 2006
What Should a Billionaire Give — and What Should You, The New York Times, 2006
Stem Cell Research: the ethical issues. (co-edited by Lori Gruen, Laura Grabel, and Peter Singer. New York: Blackwells. 2007.
The Bioethics Reader: Editors' Choice. (co-editor with Ruth Chadwick, Helga Kuhse, Willem Landman and Udo Schüklenk). New York: Blackwells. 2007.
The Future of Animal Farming: Renewing the Ancient Contract (with Marian Stamp Dawkins, and Roland Bonney) 2008. Nova York: Wiley-Blackwell.
The Life You Can Save: Acting Now to End World Poverty. New York: Random House 2009