Born in England in 1949, Stefan played football in Leeds with Farsley Celtic in the Yorkshire League. He migrated to Newcastle, Australia in 1969 as a 19 year old and played with Weston Bears, winning 3 championships in 1971, 72 and 73 - having lost the Grand Final in 1969. He was Treasurer of Northern NSW Soccer Federation in 1978 and President 1979–82, which included the first season of Northern State League. He became a member of ASF Executive in the same year. Stefan managed the Socceroos team which won the Merlion Cup in Singapore in 1982 and then became General Manager of the National Soccer League in 1982–88 and again 1996–2004. He also held the post as CEO of NSL club Sydney Olympic from 1990–93. During his time with the NSL, Stefan and his associate Peter Russell were the motivating force behind the awarding of the Joe Marston Medal for the best player at the Grand Final and the Johnny Warren Medal for the best player in the national competition, which continue to this day. When the NSL was disbanded in 2004, Stefan continued to work for the Australian Soccer Association as a member of the implementation panel for the New National Competition (later the Hyundai A-League) which produced the Kemeny Report. Stefan returned to football administration as Head of Competitions for Football NSW from 2005-2006, CEO of the Johnny Warren Football Foundation in 2006 and later held various posts with Sydney FC, including CEO, from 2008-2013.