He first became politically active in the 1950s as a member of the local branch of the National Association for the Advancement of Colored People. He served two terms as branch president, served on Tacoma's first Human Relations Commission, and in 1968, Moss helped create the Tacoma Urban League and played a key role in securing public funding for its Urban Services Center. Moss was a dental technician, and ran a business, Northwest Porcelain Studios. He left this business in the hands of his assistants when he was hired by the Tacoma Chamber of Commerce and the Tacoma Area Coalition in the spring of 1968 to run the Central Area Employment Office, soliciting jobs for disadvantaged Tacoma-area residents. He entered electoral politics in 1969 as an unsuccessful candidate for the Tacoma City Council. A year later, five council members were recalled, and Moss was appointed to a seat, which he took on October 13, 1970. He was elected to a full term in 1971, remaining a full-time employee of the Urban League throughout this period. Urban League National Executive Director Vernon Jordan asked Moss to step down from his elected position in 1975 to avoid compromising the League's non-profit status. In a September 1978 domestic argument, Moss shot his son in the shoulder with a.38-caliber revolver. No charges were ever pressed, and the two later reconciled. By 1983, Moss was no longer affiliated with the Urban League. That year, he ran unsuccessfully for city council. In February 1987, he was appointed to fill a council vacancy, ran that fall for a full term, won, and was reelected in 1991. In January 1994, Tacoma mayor Jack Hyde suffered a fatal heart attack nearly at the start of his term. Moss, serving as deputy mayor at the time, was appointed mayor and served for two years. During his administration, Tacoma enacted a youth curfew law. Because the mayor is considered part of the city council, term limits prevented him from running as an incumbent in the 1995 election. During this period, Moss also worked as a civil-rights manager for the Washington State Department of Transportation. Moss was subsequently elected to the Pierce County Council, serving January 1, 1997 to December 31, 2004, including as council chair from 2002 to 2004, at which time he announced his retirement. He ran unsuccessfully for mayor of Tacoma in 2001, and came out of that retirement in 2007 to launch an unsuccessful run for Tacoma City Council against incumbent Spiro Manthou.
