He played on the European Tour in 1998 and 1999, also competing on Europe’s developmental Challenge Tour in 1999.
In 2000, he won the Canadian Tour Order of Merit, before moving to the United States to compete on the Nationwide Tour in 2002.
He was successful enough to graduate to the full PGA Tour in 2003, but was unable to retain his card and returned to the development tour from 2004 to 2006.
In 2007 and 2008, he went back to Europe to play on the European and Challenge tours. He returned to the Nationwide Tour (now Web.com Tour) in 2009.
At the 2014 Cleveland Open on the Web.com Tour, Alker beat South Africa’s Dawie van der Walt on the 11th playoff hole, a tour record for longest playoff.
He finished 20th in the Web.com Tour Finals to earn his PGA Tour card for the 2014–15 season.
In 2016, Alker played in the Open after tying for second in the Final Qualifying event held at the Royal Cinque Ports Golf Club.