Head of the Los Angeles County Federation of Labor from 1996 until his death in 2005, Contreras was responsible for transforming the Los Angeles labor movement into a political force by mobilizing the immigrant workforce. Born into a family of farm workers, he started his career in labor as an activist and organizer for the United Farm Workers union. 
Los Angeles Martinez Jobs Bill support rally
On October 18 1997, Matthew Martinez, State senators Hilda Solis and Diane Watson, City Councilman Richard Alarcon, Miguel Contreras, executive secretary-treasurer of the Los Angeles Federation of Labor and Geraldine Washington, president of the Los Angeles NAACP addressed a Los Angeles "show us the living wage jobs" rally, as part of a national day of action, calling on Congress to pass the Martinez Jobs Bill. there were concurrent rallies in nearly 20 cities, organized by the Communist Party USA dominated National Labor-Community Coalition For Public Works Jobs. Pastor Cecil Murray of the First AME Church in South Los Angeles sponsored the rally.
Socialists organize to "challenge for power" in Los Angeles
Tarzynski listed 25 people he thought should be on an "A-list" of "25 or so leaders/activists/intellectuals and/or "eminent persons" who would gather periodically to theorize/strategize about how to rebuild a progressive movement in our metropolitan area that could challenge for power."
Tarzynski listed himself, Harold Meyerson, Karen Bass, Sylvia Castillo, Gary Phillips, Joe Hicks, Richard Rothstein, Steve Cancian, Larry Frank, Torie Osborn, Rudy Acuna, Aris Anagnos, Abby Arnold, Carl Boggs, Blase Bonpane, Rick Brown, Stanley Sheinbaum, Alice Callahan, Jim Conn, Peter Dreier, Maria Elena Durazo, Miguel Contreras, Mike Davis, Bill Gallegos, Bob Gottlieb, Kent Wong, Russell Jacoby, Bong Hwan Kim, Paula Litt (and Barry Litt, with a question mark), Peter Olney, Derek Shearer, Clancy Sigal and Anthony Thigpenn.
Included in a suggested elected officials sub-group were Mark Ridley-Thomas, Gloria Romero, Jackie Goldberg, Gil Cedillo, Tom Hayden, Antonio Villaraigosa, Paul Rosenstein and Congressmen Xavier Becerra, Henry Waxman and Maxine Waters.
Tarzynski went on to write "I think we should limit the group to 25 max, otherwise group dynamics begins to break down....As i said, I would like this to take place in a nice place with good food and drink...it should properly be an all day event."
Cesar Chavez rally
On November 6 1999, a rally was held in Los Angeles, at Placita Olvera kiosk, calling for a holiday to mark the birth of Cesar Chavez. Contact for the rally was Evelina Alarcon of the United Farm Workers and the Communist Party USA.
Speakers included Dolores Huerta of the UFW, and Majority leader of the California State Senate, Richard Alarcon, who introduced Senate Bill-984, which would make March 31, Chavez's birthday a paid public holiday.
Also speaking were Los Angeles Board of Supervisors member Gloria Molina, who introduced a similar measure at county level, Art Pulaski, of the California State Federation of Labor executive, Los Angeles City Council member Jackie Goldberg, Los Angeles Federation of Labor executive member Miguel Contreras, and Paul Chavez, son of Cesar, and president of the National Farm Worker Service Center.
Former Speaker of the State Assembly Antonio Villaraigosa made history on March 4 2003, when he won an East Los Angeles seat in the 14th council district of the nation’s second largest city.
Villaraigosa, a former organizer for the United Teachers of Los Angeles, ascended with 56 percent of the vote, taking the seat away from Councilman Nick Pacheco, and, for the first time in the city’s history, defeating an incumbent councilman in a primary election.
“We are going to organize families and work together to elevate the quality of life of this district,” said an emotional Antonio Villaraigosa to hundreds of labor union and community supporters who filled the Plaza del Sol hall in Boyle Heights, a working class, Mexican American and immigrant community. “This victory clearly says that we will not be forgotten. We are human beings and we deserve respect,” he continued as volunteers cheered, cried, and chanted, “Si se puede!”
“This is just the beginning,” said the jubilant Miguel Contreras, executive secretary treasurer of the Los Angeles County Federation of Labor, who chaired the election night celebration.