Career
United in Major League Soccer. Youth
However, after not being able to break into the first-team for Club Brugge, he decided to sign with German Bundesliga side 1. FSV Mainz 05, where he spent the next four seasons playing with the reserve side.
District of Columbia United
On July 3, 2013 it was announced that Jeffrey had been picked up by Major League Soccer side District of Columbia United in a waiver draft that sent him to Washington District of Columbia. He then made his professional debut for District of Columbia United on July 27 against the New England Revolution in which he started and played 79 minutes as District of Columbia United lost the match 1–2.
On August 3, Jeffrey scored his first goal with his new club, netting a pass from Conor Doyle to give United a 3–1 lead against Montreal Impact. Jeffrey had represented the United States at the under-17, under-20, and the under-23 levels.
Jeffrey spent three semesters in the U-17 men’s national team residency program, where he led all players with 39 caps. The midfielder tallied once with a late penalty against Tunisia in the group stages.
He captained the under-17 side during the 2007 Fédération internationale de football association U-17 World Cup and had played for the u20 side during the 2009 Fédération internationale de football association U-20 World Cup.