Campbell recorded prolifically throughout the 1960s; notable early ska releases include: "Madness" (1963), "Wash Wash" (1963, with Ernest Ranglin on bass), "One Step Beyond" (1964) and "Al Capone" (1964). The documentary This is Ska (1964), hosted by Tony Verity and filmed at the Sombrero Club, includes Campbell performing his Jamaican hit "Wash Wash". In 1964 Campbell met World Heavyweight Champion boxer Muhammad Ali who invited him to attend a Nation of Islam talk at Mosque 29 in Miami. That year Campbell joined the Nation of Islam and also started to release material, including a version of Louis X's "White Man's Heaven is a Black Man's Hell," on his own imprint label called "Islam". In 1965 he appeared in Millie in Jamaica (a film short about Millie Small's return to Jamaica after the world-wide success of "My Boy Lollipop") which was broadcast on Rediffusion's Friday evening pop show Ready, Steady, Go! Campbell had a top twenty hit in the UK with the single "Al Capone" (no. 18, February 1967). He toured the UK in spring 1967 appearing at the Marquee Club in May and later toured America to promote the RCA Victor LP release The Ten Commandments (From Man To Woman). "Ten Commandments" reached #81 on the Billboard Hot 100, becoming his only hit single in the United States. By the late 1960s Campbell was once again at the forefront of a musical change in Jamaica; the new music would be called rocksteady. Campbell tracks like "Shaking Up Orange Street" (1967) were arranged with the slower, more soulful rocksteady template as used by Alton Ellis ("Rock Steady") and many others. The album Judge Dread Rock Steady was released in 1967, and the title track "Judge Dread" with its satirical theme and vocal style proved to be popular to the point of parody. In 1968 the compilation album FABulous was released, opening with the track "Earthquake" (which revisited the theme of Orange Street) and including earlier hits. The album has regularly been reissued in the UK.