James Kingston Stellin was born on the 5th of July, 1922 in Lyall Bay, Wellington. He had one blood sister named Beatrice (Junior) and one half sister named Marie. His mother was Beatrice Stellin (Senior), and his father was James Stellin (Senior), who was a well-known property developer in Wellington. His family seemed to like juniors and seniors.

He also had a cousin named Dion who also went to war, in the Marines and served in Crete and Italy. James's nickname was "Joe" even though the shortened version of James is "Jim".

He was educated at Scots College, where there is a library named after him. He joined the New Zealand Air Force in 1942, and left for England to join the RAF the following year. He was killed saving a village school in August 1944.