Towell grew up in a large family in rural Ontario, attending local schools. At college, he studied visual arts at York University in Toronto, where his interest in photography first began. In 1976 Towell volunteered to work in Calcutta, India, where he became interested in questions about the distribution of wealth and issues of land and landlessness. 
Returning to Canada, Towell taught folk music and wrote poetry. He became a freelance photographer in 1984. His early work included projects on the Contra war in Nicaragua, the civil war in El Salvador, relatives of the disappeared in Guatemala, and American Vietnam War veterans who worked to rebuild Vietnam. His first magazine essay looked at the ecological damages from the Exxon Valdez oil spill.
In 1988, Towell joined the Magnum photo agency, becoming the first Canadian associated with the group. He has had picture essays published in The New York Times, Life, Rolling Stone, and other magazines. His work has included documentation of the Palestinian-Israeli conflict, Mennonite migrant workers in Mexico, and a personal project on his family's farm in southern Ontario.
He always works with traditional film, eschewing digital options: “Black and white is still the poetic form of photography. Digital is for the moment; black and white is an investment of time and love.” He has also worked with panoramic cameras, which allow him to shoot the “landscapes of destruction”--looking at human beings and their place in the landscape.
Towell’s bibliography includes books of photographs, poetry, and oral history. He has also recorded several audio CDs of original poetry and songs. Towell lives in rural Lambton County Ontario and sharecrops a 75-acre farm with his wife Ann and their four children.
- 2009: The World From My Front Porch, Top ten best photo books of 2008, Photo-Eye
- 2009: The World From My Front Porch, And/or Photography Book Award(Kraszna-Krausz Foundation, UK- shortlisted)
- 2009: The World From My Front Porch, one of “50 Best” photo books of the year. Festival Of The Photograph. Charlottesville, VA
- 2008: One of the year’s best pictures, Photo District News
- 2007: Achievement In Filmmaking Award, New York Independent Film And Video Festival
- 2007: Alicia Patterson Award (USA, Finalist)
- 2006: PDN Photo Annual: One of the year’s best projects
- 2000: Society for News Design Award, La Nacion
- 2000: Photo-eye Award, Citation of Excellence
- 1999: Hasselblad Foundation Award
- 1999: Roloff Beny Book Award
- 1999: Picture Of the Year (Best Use of Photography in Books)
- 1998: 1st Prize, Alfred Eisenstaedt Award
- 1998: ‘Pictoral’ Prize, Pictures of the Year Foundation, University of Missouri
- 1998: Overseas Press Club, New York, Citation of Excellence
- 1998: Society of Publication Designers, Magazine of the Year,"The New York Times"
- 1998: Society of Publication Designers, Merit Award, "The New York Times Magazine"
- 1997: Golden Light (Best Monograph Award)
- 1996: Oskar Barnack Award
- 1996: El Mundo Award
- 1995: Ernst Haas Foundation Award
- 1994/95: Gold Medal, Canadian National Awards
- 1994: Picture of the Year, Canon Photo Essay Award
- 1994: World Press Photo, 1st Prize in category ‘Daily Life Stories’, 1st Prize in category
- ‘General News Stories’
- 1994: Premier Photo of the Year, World Press Photo
- 1993: 1st Prize in category ‘Daily Life Stories’, World Press Photo
- 1991/93: Gold Medal, Western Canada Magazine Awards
- 1991: W. Eugene Smith Foundation Award
- 1991: Silver Medal, Canadian National Awards
- 2012: Royal Ontario Museum, Toronto, Canada
- 2008: George Eastman House, Rochester, New York
- 2006: FOAM, Amsterdam, Netherlands
- 2005: No Man's Land - Fondation Henri Cartier-Bresson, Paris, France
- 2001: National Portrait Gallery, Edinburgh, UK
- 2001: Canadian Museum of Contemporary Photography, Ottawa, Canada
- 1997: Noorderlicht Photo Festival, Groningen, Netherlands
- 1997: Circulo de Bellas Artes, Madrid, Spain
- 1994: Retrospective - Nieuwekerk, the Netherlands
- 1994: Carnets de Voyage - Canadian Museum of Contemporary Photography
- 1991: Le Mois de la Photo - Maison de la Culture Plateau, Montreal, Canada
- Ruins: Afghanistan (2009)
- The Cardboard House: MSF Peru - Action on Aids. Trolley Books. 2008. ISBN 978-1-904563-71-6.
- The World From My Front Porch (2008)
- In the Wake of Katrina (2006)
- No Man's Land (2005)
- The Mennonites (2000)
- Then Palestine (1999)
- El Salvador (1997)
- House on Ninth Street (1994)
- The Prison Poems of Ho Chi Minh (1992)
- Somoza's Last Stand (1990)
- Gifts of War (1988)
- Burning Cadillacs (1983)
- "Larry Towell biography". Magnum Photos. Retrieved 2006-12-28.
- "Larry Towell biography". Bulger Gallery. Retrieved 2011-01-12.
- "Larry Towell article". Walrus Magazine. Retrieved 2011-01-12.
- "Larry Towell and Donovan Wylie: Afghanistan". CONTACT Photography Festival. Retrieved 2014-10-07.
- "Larry Towell: The World From My Front Porch at Eastman House Feb. 16 through June 15". George Eastman House. Archived from the original on 2008-06-01. Retrieved 2008-04-27.