Simon French was born in Paddington, Sydney, and was educated at schools in the suburb of Blacktown. At Blacktown High School he was co-editor of a school newspaper and wrote his first novel Hey Phantom Singlet (1975). After high school he worked for some time at Blacktown Library before qualifying as a primary school teacher at the Mitchell College of Advanced Education in Bathurst. At Mitchell College, French worked as an announcer for the college radio station and co-edited the college newspaper. He also wrote his second book Cannily, Cannily (1981).
After graduating, French worked as an infant school teacher and youth worker while working on his third book, All We Know (1986). French's books have been regularly shortlisted for Children's Book Council Book of the Year Awards with All We Know winning in 1987. In 1991 French published Change the Locks and, after a 10 year hiatus, he wrote Where in the World and Guess the Baby. Both books received favourable attention from award judges. French's books frequently explore the struggle of individuals trying to cope with change and difference in closed and open societies.
In 2019, French was in his 36th year of teaching. He also spent four years working in an inner-city children's refuge, which influenced hie work Change the Locks.
French is married to illustrator Donna Rawlins.