LELO was founded as the Northwest Labor and Employment Law Office in Seattle, Washington in 1972 when Black workers from the United Construction Workers Association, Asian workers from the Alaska Cannery Workers Association and Latino workers from the Northwest Chapter of the United Farmworkers of America came together to work for racial and economic justice.

In the 1970s, LELO used the 1964 Civil Rights Act to file class action lawsuits and direct action as a means to empower workers of color and further support the grassroots organizing of the three founding groups. LELO's first lawsuits were launched on behalf of Black construction workers, led by Tyree Scott and the United Construction Workers Association. Through LELO's legal action and grassroots organizing, the number of Black workers in the Seattle construction trades rose from less than 10 in 1970 to more than 600 in 1979.

With money raised through the victories of their initial UCWA lawsuits, LELO was able to launch successful suits on behalf of Asian, Pacific Islander and Native Alaska cannery workers and then later, on behalf of farmworkers and their right to organize. In Venegas v. UFW-WA, LELO successfully fought an injunction that a ranch owner had obtained to deny farmworker organizers the right to enter migrant camps to meet with workers. This case set an important national precedent in securing access of union organizers to migrant farmworkers.

Two of LELO's founding board members, cannery union officers Silme Domingo and Gene Viernes were murdered in 1981 on the orders of former President of the Philippines Ferdinand Marcos. LELO leaders responded to this tragedy by joining a broad coalition that became a national and international movement over an 8 year period that called for justice in the murders. In 1991 the Domingo and Viernes families were awarded $ 23.5 million in a precedent setting verdict that represented the first time a head of state of a foreign government was held accountable for the assassinations of U.S. citizens on U.S. soil.

Since the 1980s, LELO has organized to advocate for project labor agreements to increase employment of workers of color in large public works projects, advocated for creation of family wage jobs, and organized projects to promote international worker solidarity. In the 2000s, LELO worked to mitigate punitive traffic law enforcement that resulted in working people losing drivers licenses, and subsequently, their jobs. Its re-licensing program supported working with courts to restore driving privileges of workers in apprenticeship programs and in low-income communities.

In the 1990s, LELO was renamed Legacy of Equality, Leadership and Organizing