Boston Globe | JUNE 28, 2013 | By Meghan E. Irons

State Representative Martin J. Walsh said his focus would be economic development in downtown Boston. He also cited his record on jobs and fighting for working families.

The Greater Boston Labor Council, a federation of 154 unions in the area, endorsed state Representative Martin J. Walsh Thursday as their candidate for Boston mayor, citing his background as a union crusader.

The 90,000-member council announced its decision after a voice vote conducted privately in Dorchester. Council members pledged to fan out across the city and knock on doors to ensure that Walsh emerges from a crowded field as one of the two finalists for the city’s top job.

The vote came after a wide-ranging public forum at the IBEW Local 103 union hall in which Walsh and nine other candidates made their pitch for labor support.

Walsh, who represents Dorchester, cited his background as a second-generation laborer who rose through the ranks of his union, Laborers Local 223, to head the Building and Construction Trades Council of the Metropolitan District.

“My vision for this city is clear,’’ he said at the forum attended by about 300 people, according to organizers. “One is to continue the economic development . . . in downtown Boston so we can continue to build our city.”

Praising the endorsement afterward, Walsh said he has a proven track record of working to create jobs, fighting for working families, and bringing government, business, and labor to the negotiating table.

With the endorsement, Walsh put Felix Arroyo, a former union organizer and current Boston councilor, out of the council’s consideration.

The council’s decision also comes as major organizations are beginning to size up the candidates and coalesce around their favorite. EMILY’s List, the nation’s largest resource for women in politics, recently endorsed Charlotte Golar Richie for mayor.

Rich Rogers, executive secretary for the council, said 66 of the council’s affiliates were represented at Thursday’s forum. The Boston Teachers Union, which had members there, did not vote, Rogers said.

He added that a big part of the council’s strategy is to have Walsh in a second-, third-, or fourth-place in most neighborhoods, particularly those where he is not as popular.

“Everybody has a turf,’’ said Rogers. “But union members are in every ward in the city, and we’re going to go to all their doors. “

Before the event, the candidates filled out a nine-page questionnaire asking their positions on development, increasing city revenue, and boosting living wages for working families. The candidates were asked at the forum to defend their positions.

They seemed to vary little on the issues. Most said they would meet regularly with labor leaders, work with the teachers unions to improve struggling schools, and look for fresh ways to bring new sources of revenue into the city.

Meghan Irons can be reached at mirons@globe.com. Follow her on Twitter @meghanirons.