The Martin Luther King, Jr. County Labor Council (MLKCLC) is the central body of labor organizations in King County, Washington. The MLKCLC is affiliated with the national AFL–CIO, the central labor organization in the United States, which represents more than 13 million working people. Over 125 organizations are affiliated with the MLKCLC, and more than 75,000 workers belong to Council-affiliated organizations. In addition to supporting labor organizations, it acts as a voice for the interests and needs of the working people in King County, WA.

The core responsibilities of the MLKCLC are to assist workers and their unions in the struggle for social and economic justice; support efforts to organize and bargain fair contracts; lobby, endorse and involve working people in the political process; advocate and support laws that protect working people; support community services outreach work; and unite with community allies who are also struggling for justice.

In 1888, the West Central Labor Union (WCLU) was organized by its first president, O.F. Wegener, in Seattle, Washington. The WCLU is the first of many names the Council has adopted over the years. Despite being a union itself, the WCLU represented almost every trade and labor union in the area including the Knights of Labor Assembly and the Miners Unions of Newcastle, Cedar Mountain and Renton.

One of the many ways the WCLU promoted their cause of workers' rights was through Labor Day Parades held on Labor Day. The parades represented every trade union of Seattle with AFL and Knights of Labor leaders' pictures displayed throughout the parade. [Central] Along with Labor Day Parades, the WCLU advocated for workers by obtaining direct control over its newspaper the Union Record in 1903 by buying it from its publisher. The Union Record was the "official organ" of the WCLU and it strived to exclude politics, emphasizing that it was "not a socialist paper."

In 1891 Oregon Improvement Co. brought in hundreds of black laborers from the South into various mining towns in King County to break labor disputes. The Miners Unions responded by appealing to the WLCU for moral and financial support. In spite of strong support the mine owners prevailed in large part due to the economic depression at the time. [Central] As a result of this defeat, the Knights of Labor and trade unions in the WLCU went into a period of decline.

Although the WCLU aimed at promoting fair labor by operating its own employment referral "hiring hall," in 1893 public criticism of this effort arose centered around complaints of excessive fees and fictitious jobs. This criticism prompted the WCLU to collaborate with the unorganized workers which, along with W.G. Armstrong of the Typographers Union, worked to pass an ordinance by the city council which established the free employment bureau. [Central] The bureau was solidified by the charter provision and consolidated with the Civil Service Department in 1895. During this time, the charter reelected 15 freeholders from organized labor and addressed eight-hour work days and safety inspection of boilers in the work place.

The late 1800s and early 1900s saw a growth in the organization and an increase in union memberships. In 1900 several new unions – Cooks and Waitresses Union, Barbers Union, Leather Workers Union and Telephone Operators Union – were organized and joined the WCLU. Due to the growth, $14,000 was raised to build a new Labor Temple in Seattle, Washington. [Central] Mainstay unions of the WCLU at this time were the Sailors, Brewery Workers, Cigarmakers, Tailors, Stonecutters, Typographers, Iron Molders, Stage Employees, Musicians, Bricklayers, Printing Pressmen and Newsboys unions.

In 1905 the WCLU changed its name to the Central Labor Council of Seattle and Vicinity, which was often called the Seattle Central Labor Council (SCLC) or simply the Central Labor Council. The council was a key supporter of the Populist movement, as represented by the organizing of the People's Party during the rise and fall of the progressive coalition from 1909 to 1917.