Newton was born and raised in north Derbyshire and was educated at Chesterfield Grammar School. He graduated from Bristol University. He received his D.Phil. and D.Sc. degrees from the University of Oxford and has studied a wide range of bird species.
He has been interested in birds since his childhood. As a teenager he became particularly fascinated by finches and undertook doctoral and post-doctoral studies on them. Newton conducted a 27-year study of a Eurasian sparrowhawk population nesting in southern Scotland, which resulted in what many consider to be the most detailed and longest-running study of any population of birds of prey.
Before retirement, he was Senior Ornithologist at the United Kingdom's Natural Environment Research Council. He has also been head of the Avian Biology Section at the Monks Wood Research Station (1989–2000), Chairman of the Board of The Peregrine Fund, Chairman of the Council of the Royal Society for the Protection of Birds and visiting professor of ornithology at the University of Oxford. Newton has also held the positions of President of the British Ornithologists' Union and the British Ecological Society (1994–1995).
Honours and awards
- Union Medal of the British Ornithological Union (1988)
- Gold Medal of the Royal Society for the Protection of Birds (1991)
- Fellow of the Royal Society (1993)
- Fellow of the Royal Society of Edinburgh (1994) 
- Elliot Cowes Award of the American Ornithologists' Union (1995)
- Order of the British Empire (1999)
- Finches (Collins New Naturalist Library) (1972)
- Population Ecology of Raptors (1979) T & A.D. Poyser. ISBN 978-1408138533
- The Sparrowhawk (1986) T & A.D. Poyser. ISBN 0-85661-041-0
- Population Limitation in Birds (1998)
- The Speciation and Biogeography of Birds (2003)
- The Ecology of Bird Migration (2007)
- Bird Migration (Collins New Naturalist Library) (2010) ISBN 978-0-00-730731-9 (HB), ISBN 978-0-00-730732-6 (PB)
- Ian Newton | Collins. The New Naturalists Online. Retrieved 3 December 2009
- Newton, Ian (1986) The Sparrowhawk. T & A.D. Poyser Ltd. Calton. ISBN 0-85661-041-0
- Ian Newton. The Migration Ecology of Birds. Buteo Books. Retrieved 3 December 2009
- Newton, I. (2009) Introduction. In R.T. Watson, M. Fuller, M. Pokras, and W.G. Hunt (Eds.). Ingestion of Lead from Spent Ammunition: Implications for Wildlife and Humans. The Peregrine Fund, Boise, Idaho, USA. DOI 10.4080/ilsa.2009.0091
- Ian Newton. Researcher Results. The Peregrine Fund. Retrieved 3 December 2009
- "RSE Fellows" (PDF). Royal Society of Edinburgh. Retrieved 10 January 2011.