Ibrahimovic set a single-season scoring record for Galaxy with his 25th goal – surpassing Carlos Ruiz's previous mark of 24 in the 2002 season – before moving further onto 26 goals, netting a hat-trick in a 7-2 thrashing of Sporting Kansas City at Dignity Health Sports Park.
Galaxy had fallen behind to a Felipe Gutierrez goal before Ibrahimovic equalised just after the half-hour mark.
The former Manchester United striker had a penalty saved by Tim Melia, only for the rebound to fall kindly for him to tap in.
Joe Corona headed in a Cristian Pavon cross to give Galaxy the lead in the second half before Ibrahimovic broke the club's record with a finish from inside the area.
Sebastian Lletget scored a late brace after an Uriel Antuna goal before Ibrahimovic completed his hat-trick, drilling into the bottom corner after an Efrain Alvarez pass.
Gutierrez scored a late consolation goal for Sporting as Galaxy climbed into fifth in the Western Conference.
A first-half own goal from Bill Tuiloma was enough for DC United to overcome the Portland Timbers 1-0.
It marked a second straight league win for DC, who are fifth in the Eastern Conference and eight points clear of eighth-placed Montreal Impact.
Toronto are fourth and also closing in on the play-offs after recording a 3-2 win at home to Colorado Rapids.
Jonathan Osorio scored the match-winner for Toronto in the 70th minute.
Darwin Quintero's brace helped Minnesota United to a 3-1 victory over Real Salt Lake and Nicolas Lodeiro's double saw Seattle Sounders beat New York Red Bulls 4-2.