Olsen's coaching career began at the beginning of the 2010 season as an assistant under United head coach Curt Onalfo. Midway through the 2010 campaign, Olsen replaced Onalfo, making his debut as Interim Head Coach on August 7 at New England. Olsen won his first match in charge on August 22 against Philadelphia in a 2-0 triumph. Following improved play under the former United captain, Olsen was hired permanently as Head Coach on November 29, 2010. At 33-years-old he was, at the time, the youngest coach in Major League Soccer.
In 2011, his first full season at the helm, Olsen's side made big strides as the team finished 9-13-12 and was in the playoff hunt until the final week of the season. The club's offense saw vast improvement that year scoring 49 goals – good enough for fourth most in MLS. Like its coach, D.C. United showed pride, brining the momentum from a much-improved season into a very successful 2012 season.
In his second full season as head coach, Olsen’s side reached the playoffs for the first time in five years and the first such appearance for Olsen as head coach. With the third best regular-season record in all of MLS, United captured the #2 seed in the East, defeating the New York Red Bulls in the Eastern Conference semifinals and losing to the Houston Dynamo in the conference finals. On the offensive side, the Black-and-Red netted 53 goals, good for fourth in the League. Perhaps more impressively, the team went undefeated at home in 16 games (12-0-4), dating all the way back to March 30. At season’s end, Olsen was named a finalist for MLS’ Coach of the Year.
2013 proved a tough season for the leader of the Black-and-Red, but Olsen and his squad never lost hope. Though finishing with an MLS-worst record of 3-24-7, United won all five of its U.S. Open Cup matches, capturing the title and brining home D.C. United’s 13th trophy— an MLS best.
As a player, Olsen was amongst the club's all-time leaders in several key categories at the time of his retirement – second in games played (221), minutes played (17,098) and game-winning goals (13), third in assists (49) and shots on goal (155), and seventh all-time in goals (29). Always a United fan favorite, the midfielder won nine total trophies while in DC, including two MLS Cups (1999 & 2004). He was a two-time All-Star (1998 & 1999), the 1998 MLS Rookie of the Year, the 1999 MLS Cup MVP, the 2003 USSF Humanitarian of the Year and was named to the MLS Best XI in 2007. He retired from the Black-and-Red lineup on November 24, 2009.
In addition to his storied career with United, Olsen also played with the U.S. Men's National Team. He made his full international debut against Australia on November 6, 1998. His first goal for the U.S. came in just his second international game when he scored against Chile on February 21, 1999. In 2000, he was part of the team that reached the bronze medal game at the Sydney Olympics before falling to Chile. Olsen was selected to the 2006 World Cup team. In his career, the midfielder earned 37 caps and six goals with the U.S. Men's National Team.
Prior to his professional career, Olsen spent three seasons at the University of Virginia from 1995-1997. During his time with the Cavaliers, the team posted a 56-8-8 record. The midfielder compiled 34 goals with 41 assists and started and played every game (69) of his collegiate career. After his junior season, he was named the 1997 Soccer America Player of the Year and was a finalist for the Hermann Trophy. He was also named as the ACC Tournament MVP and selected to the NSCAA All-American first-team after his senior year.