Beckham had been out of action since March 14, when he tore his left Achilles' tendon while playing for AC Milan on loan. The injury kept the midfielder from playing in his fourth World Cup for England.
Beckham replaced Juninho in the 70th minute to loud cheers and a partial standing ovation. Four minutes later, Beckham received a yellow card for a dangerous foul against Emmanuel Ekpo.
Edson Buddle, Dema Kovalenko and Jovan Kirovski scored and Landon Donovan had two assists to help the Galaxy (14-5-5) regain the top spot in Major League Soccer's Western Conference, three points ahead of Real Salt Lake.
Andres Mendoza scored for the Crew (13-6-5), whose lead over second-place New York in the Eastern Conference was cut to four points.
Buddle opened the scoring in the 13th minute, volleying Sean Franklin's cross from the right wing off his right instep and inside the left post from 8 yards. The goal was Buddle's league-leading 14th and his first since Aug. 14.
Galaxy goalkeeper Donovan Ricketts stopped a potential tying goal in the 20th minute by blocking Steven Lenhart's 11-yard shot off a breakaway with his chest.
Kovalenko made it 2-0 in the 35th minute with his first goal in two years. A sequence of passes from Kovalenko to Kirovski to Donovan ended with Kovalenko receiving the ball from Donovan and converting from 13 yards. Kovalenko last scored on May 31, 2008, for Real Salt Lake. Donovan's assist was his league-leading 14th.
Kirovski made it 3-0 in the 55th minute on a 5-yard header off Alex Cazumba's 30-yard free kick. Mendoza scored in the 85th minute on a 16-yard shot.
Buddle left the game as the second half began because of leg cramps.