Career
Popović started his professional career in FK Čukarički Stankom and played for the club between 2000 and 2009, he also made a small appearance in Ligue 2 with Stade Brestois 29 in the 2005/2006 season. In March 2009 he made a move to South of Korea and Daegu Football Club. However, he was released in June 2009 from the club after failing to score goals. In August the same year Popović signed a contract with the Bosnian side FK Željezničar Sarajevo.
After Popović have been released from his contract with Željezničar, he had an unsuccessful trial with Albanian Superliga team KF Skënderbeu Korçë in June 2011.
In December 2011, he signed with Malaysia Super League side Perak FA. Earlier reports from Malaysian media quoted Perak management have released Popović from his contract on 1 April 2012, however later reports stated that Perak management have retained his services until 16 April, the last day for registration window for import players. He ended his stint with Perak with only one goal in 16 appearances in all competitions (14 league matches and 2 cup matches).
After his release from Perak, he returned to Europe to join Albanian Superliga team FK Kukësi for the 2012-2013 season. Lazar appeared for the Serbia and Montenegro U-21 and U-23 teams during 2004-2006.