Debuting with North Melbourne in 1996 as a 17-year-old, Welsh was seen as a development player who started to get regular game time in 1998.
Though he was drafted as a half-back flanker, Welsh played with North Melbourne as a forward and was a part of North Melbourne's premiership side in 1999 before, citing homesickness, returning to Adelaide in 2000 to play for Adelaide Football Club.
Welsh finished with 49 goals and 20 behinds for the season, topping the Crows goalkicking list for the fourth time.
Welsh announced his retirement at the end of the 2009 season after missing out on the Grand Final with the Bulldogs.
Post AFL Welsh had a stint at the Encounter Bay Football Club notably leading the goal kicking in 2013 in a premiership year.