Mabhida was drawn to trade unionism by the late Harry Gwala, then an ardent unionist and member of the South African Communist Party.
After many unionists were banned in 1952, his colleagues in the newly revived underground party urged Mabhida to undertake full-time union work.
He also served as secretary of the African National Congress (ANC) Pietermaritzburg branch in the mid-1950s, and had a close working relationship with Albert Luthuli.
He was elected General Secretary of the Communist Party in November 1979, replacing Moses Kotane who had died the previous year.
In 1985, while on a mission to Havana, Mabhida suffered a stroke, and after a year of illness, died of a heart attack in Maputo and was buried there on 29 March 1986.