Former Assembly Speaker Bob Hertzberg, who narrowly missed making the L.A. mayoral runoff last month, endorsed City Councilman Antonio Villaraigosa on Thursday.

“I am endorsing Antonio because he is the leader Los Angeles needs he will roll up his sleeves and get big things done,” Hertzberg said at a biomedical facility in Sylmar Thursday morning. Gloria Molina, a longtime friend of both Hertzberg and Villaraigosa, was on hand. “Antonio has the vision and energy to move Los Angeles forward, and I am committed to being his partner in making that happen.”

Hertzberg later said he intends to be an active participant in Villaraigosa’s campaign, “raising money, outreaching to the community, contributing ideas or whatever else he wants me to do.”

Villaraigosa pledged to work with Hertzberg as mayor. “I am proud to stand here with Bob Hertzberg and receive his endorsement,” Villaraigosa said. “We are both committed to making Los Angeles a city where we are growing and prospering together.”

Hertzberg’s endorsement, which was also sought aggressively by incumbent Mayor James Hahn, is expected to boost Villaraigosa’s support in the San Fernando Valley in the final month of the runoff campaign.

It also adds momentum to the Villaraigosa campaign. Earlier this week, former basketball superstar Earvin “Magic” Johnson endorsed Villaraigosa, and on Wednesday, a Los Angeles Times poll showed Villaraigosa with an 18-point lead. Last week, City Councilman Bernard Parks who also missed the mayoral runoff endorsed Villaraigosa.

After an unconventional campaign featuring catchy television ads, Hertzberg lost out to Hahn in the March primary for the second spot in the runoff, losing by just 6,500 votes. (Villaraigosa placed first.) Two weeks later, Hertzberg met with both Villaraigosa and Hahn in highly publicized lunches at Art’s Deli in Studio City.

Hertzberg’s endorsement of Villaraigosa means that the two have managed to patch their long-strained relationship back together. The two were once roommates in Sacramento; Hertzberg collared votes for Villaraigosa to be elected speaker and Villaraigosa returned the favor by designating Hertzberg as his successor.

The two had a falling out during the speakership transition, but both were civil towards each other during the primary as they aimed their fire at Hahn.

“The stakes for the city are just too high here for there to be any issues between us,” Hertzberg said Thursday.