A bustling but skilful forward with reputation for hot-headedness, he played in 118 games and scored 42 goals for Olympic. His 16 goals in 1982 remained a club record until 1996.
At a national level, Soper played 29 times for the Socceroos, scoring four goals, mostly in "B" matches against club teams.
In 1995, he top scored (11 goals) for Perak FA in the Malaysian first division.
Soper trialled with Arsenal FC.
In later years he coached the Fairfield Bulls and Illawarra Lions.
In late 2010 it was announced that he would become a coach for Newcastle United Jets.