Jon Stephen Cleary was born on November 22, 1917, in one of the tougher, poorer districts of Sydney, New South Wales, Australia. His father, Matthew Cleary, was a laborer, and his mother, Ida Brown Cleary, a homemaker; after Jon’s birth, six more children were eventually born to them. Cleary has written that he has some of his father’s working-class temperament and some of his mother’s tightfistedness. He attended the Marist Brothers School at Randwick, New South Wales, from 1924 to 1932. He left school at age fifteen and worked at a variety of jobs, including commercial traveler, delivery man, laundry worker, sign painter, bush worker, and commercial artist.
When Cleary entered the army in 1940, he was considering a full-time career in commercial art. He served in the Australian Imperial Forces in the Middle East, New Guinea, and New Britain until 1945 and began to write during this period. By the time of his discharge, he had attained the rank of lieutenant and had sold several stories to American magazines. He had enough money to support himself for two years, during which time he planned to discover whether he could earn his living as a writer. With the exception of his employment as a journalist with the government of Australia News and Information Bureau in London (1948-1949) and in New York (1949-1951), he has worked exclusively as a freelance writer of fiction since 1945.
In 1946, Cleary met Constantine “Joy” Lucas, a resident of Melbourne, Australia, on a ship bound for England. They were married on September 6, two weeks after disembarking, and eventually became the parents of two daughters, Catherine and Jane. Joy died in 2003. Cleary, a practicing Roman Catholic, is essentially apolitical but has stated that he leans slightly to the left. He published a collection of short stories, These Small Glories, in 1946 and began producing books at the rate of nearly one per year.
Cleary is also a dramatist and scenarist. He lives in New South Wales but travels constantly. Many of his stories are set in remote locales, and he has asserted that he never writes about a region of which he does not possess firsthand knowledge. His writing career has been marked by continued success in several fields of fiction.