Erwin crossed to Coburg in the VFA during the 1968 season and was captain/coach from 1969 to 1972, leading the Lions to the 1970 2nd Division premiership.
Ahead of the 1974 season, Coburg traded Erwin to Port Melbourne for Peter Smith.
In 1975 Erwin was appointed captain-coach of Diamond Valley League team Templestowe, but Port Melbourne refused a clearance and he played a second season for the Borough.
Retiring as a player, Erwin returned to Richmond as a specialist coach for two seasons.
Erwin, however was not retained as Collingwood Football Club senior coach at the end of the 1982 season and was replaced by John Cahill as Collingwood Football Club senior coach.