He attended Oregon State University on a sports scholarship and played college soccer there from 2002 to 2005,[2] where he scored 18 goals and assisted on 30 while appearing in 76 matches.

In early 2007, he was on trial with various teams in Scandinavia and eventually got a short-term contract with Swedish side Östers IF (then at Superettan), that stretched from March 2007 to July 2007.

After a short stint playing indoor soccer with the New Jersey Ironmen, Johnson signed with San Jose Earthquakes for the 2008 MLS season.

On 14 July 2011, San Jose traded Johnson, an international roster spot, and allocation money to Toronto FC for Nana Attakora, Alan Gordon and Jacob Peterson.

[6] On 2 August, in the return leg of the preliminary round of the CONCACAF Champions League, Johnson scored a superb volley in the 37th minute, followed by a goal in the 47th from a misplaced pass by the Real Esteli F.C.

[9] Johnson was traded with Miloš Kocić to Portland Timbers on 12 December 2012 in exchange for Joe Bendik, a first-round pick in the 2013 MLS SuperDraft, and allocation money.