Leitch was drafted by Columbus Crew in the fourth round of the 2002 MLS SuperDraft, but only played 13 games for his hometown team in his first professional season. Leitch was traded to the MetroStars with Jeff Matteo for Ross Paule prior to the 2003 season. He became a regular in the Metro lineup late in the year, playing in 15 games. He then became an automatic starter in 2004, playing every minute of all but a single game. Originally a right back, Leitch acquitted himself well on the left flank when the Metros needed help at that position. He switched back to the right flank in 2005. Despite being named the team's Defender of the Year, he was waived by the club in the offseason and then came back to Columbus. He appeared in 24 matches in the 2006 season for his hometown club. In the 2007 pre-season, Leitch was waived again, this time by the Crew as they sought to clear roster spots. He would return to the New York franchise, now New York Red Bulls, in July. The versatile defender appeared in 12 league matches for the club, starting 11. In 2008 Leitch appeared in 17 regular season matches. He helped the club reach the 2008 Western Conference Final, starting in both matches of the Red Bulls historic upset over defending champion Houston Dynamo. The following week he helped shut outReal Salt Lake 1-0 to help the Red Bulls reach the MLS Cup Final for the first time in club history. Just prior to the start of the 2009 season on March 2, San Jose Earthquakes acquired Leitch in a trade with New York for an undisclosed sum of allocation money and one of the Earthquakes' eight international roster spots. Leitch had a career year with San Jose in 2009 appearing in 29 matches during the MLS regular season and contributing with 7 assists from his full back position. Leitch remained with San Jose through the 2011 season. At season's end, the club declined his 2012 contract option and he entered the 2011 MLS Re-Entry Draft. Leitch was selected by Los Angeles Galaxy in stage two of the draft on December 12, 2011. However, Leitch decided to retire rather than return for the 2012 season.
Coaching
On January 31, 2012, Leitch was named Technical Director for the San Jose Earthquakes Youth Development Academy. On August 10, 2015, he was promoted to Technical Director for the San Jose Earthquakes proper, including the first team as well as the Academy. On June 25, 2017, he was named the head coach of the Earthquakes, replacing Dominic Kinnear. His coaching debut was San Jose's 2-1 victory over Seattle Sounders FC in the knockout round of the U.S. Open Cup on June 28, advancing the Earthquakes to the quarterfinals for the first time since 2012 while also achieving the team's first-ever victory over another MLS team during the Open Cup. Leitch's first MLS match as head coach saw San Jose beat the LA Galaxy 2-1 at Stanford Stadium on July 1 off of a stoppage time winner from Shea Salinas. He was replaced as San Jose's head coach by Mikael Stahre on November 24, 2017, and thereafter returned to his former role as technical director.
