Born in Annandale, Virginia, Hamid was the first D.C. United Academy player to sign for the first team in September 2009. He made his professional debut in May 2010 as the youngest goalkeeper to win a game in Major League Soccer history. Hamid totalled 200 games for D.C. United, including 184 in the league. He helped the team to victory in the 2013 U.S. Open Cup and received the MLS Goalkeeper of the Year Award in 2014. In January 2018 he joined FC Midtjylland, winning the Danish Superliga in his first season.

Hamid made his senior debut for the United States national team in January 2012. He was part of their teams that won the CONCACAF Gold Cup in 2013 and 2017.