Jack Koskie commenced his formal art education by studying on a scholarship at the Hull College of Arts, but at the age of 16, he signed on as a deck-hand on a North Atlantic trawler. Migrating to Australia in 1939, Koskie worked as an engraver on the The Herald (Melbourne) . When World War II broke out, Koskie unsuccessfully tried to join the Royal Australian Navy (RAN), but eventually served as a sapper with the Australian Army during 1941-1944.
After the war, Koskie worked as a freelance illustrator and designer for numerous publishing companies, including Invincible Press and the Currawong Publishing Company. He served as chief designer for the Commonwealth Office of Education (Sydney, NSW, ca.1950), where he frequently produced cover designs for the Current Affairs Bulletin. Koskie eventually left the art field in 1954 to take up teaching at Hobart Technical College. He produced a book of maritime paintings, Ships That Shaped Australia (Angus and Robertson, North Ryde, New South Wales, 1987). In 1979, Koskie retired from his position as lecturer in printmaking at Deakin University (Victoria).