Youth and college Wallace's family moved to the United States when he was nine. He grew up in
Rockville, Maryland, played for Potomac Soccer Association and attended
The Bullis School, and played
college soccer at the
University of Maryland, College Park.
Professional D.C. United Wallace was drafted in the first round (6th overall) of the
2009 MLS SuperDraft by
D.C. United on 15 January 2009. He made his professional debut on 22 March 2009, in D.C.'s first game of the 2009 MLS season against
Los Angeles Galaxy, and scored his first career professional goal on 26 April 2009, in a 3–2 win over
New York Red Bulls. As both a defender and midfielder, Wallace played 39 regular-season games and made 36 starts over his two years with D.C. United, compiling three goals and five assists.
Portland Timbers On 24 November 2010, D.C. United traded Wallace and a fourth-round pick in the
2011 MLS SuperDraft to
Portland Timbers in exchange for
Dax McCarty and allocation money. Wallace re-signed with Portland on 6 December 2012. In summer 2014, Wallace was sent on loan to
USL Pro club
Arizona United to regain match fitness after returning from injury. Wallace returned to the
Portland Timbers at the beginning of the 2015 season. He served as a regular starter all of the regular season. In the
2015 Audi MLS Cup playoffs, Wallace played a vital role in the team's success, scoring a goal against
Sporting Kansas City in the knockout rounds. They went on to win that game in a penalty shootout 7–6 in what was the longest penalty shootout in MLS Cup playoffs history. The Timbers would go on to win the Western Conference Championship against
FC Dallas and enter their first ever MLS Cup Final. Wallace came up big in the final, scoring what would go on to be the game winner in the 7th minute. The final score was 2–1.
Arouca Wallace signed with Portuguese
Primeira Liga side
F.C. Arouca in January 2016.
Sport Recife Two months after signing with Arouca, on 30 March 2016,
Sport Recife signed Wallace on a two-year contract, expiring at the end of the 2017 season. According to some Brazilian sources, the transfer fee between Sport Recife and Arouca was 200,000 euros. Wallace went on to make 24 appearances for Sport Recife, scoring four goals in the 2016 season. Following rumors in the beginning of January 2017 that Wallace had no intentions of returning to Brazil, Wallace failed to report to the first day of preseason on 9 January 2017. Sport Recife subsequently set a deadline of 13 January 2017, for Wallace to return or present a plausible reason for non-attendance. On 16 January 2017, Wallace responded asking to be released. While Wallace and Sport Recife remained at an impasse for nearly a month, rumors began to swirl of a possible return to his former club, Portland Timbers. Wallace and Sport Recife finally reached resolution when he returned to Brazil and re-paid the club's 200,000 euro transfer fee on 1 February 2017. Sport Recife released Wallace from his contract the next day on 2 February 2017.
New York City FC Wallace signed with
New York City FC on 15 February 2017. He scored his first goal for the club on 12 March, in a 4–0 win over
D.C. United.
Sporting Kansas City On 14 December 2018, Wallace signed one-year contract with
Sporting Kansas City. He was out of contract after the 2019 season.
Retirement After nearly two-years without a club, Wallace officially retired on 13 August 2021. He signed a ceremonial one-day contract with Portland Timbers allowing him to officially retire as a Timbers player. ==International career==