Kamaru made his first breakthrough in 1967 with Celina. The height of his musical career was between 1975-1985. In the late 1980s he was the first Kenyan artist to play at the Carnivore Restaurant, then only hosting foreign artists. According to Martin Dunford, the owner of the restaurant, Kamaru's vibrant performance opened doors for other Kenyan artist to perform at the venue.
Many of his songs were political, either praising or criticising the government. Initially he had a good relationships with president Jomo Kenyatta, but after writing a song condemning the murder of Josiah Mwangi Kariuki in 1975 Kamaru fell out with him. After Kenyatta died, the next president Daniel arap Moi was close to the artist. In 1980 Kamaru toured Japan as a part of President Moi's entourage. After the visit he composed Safari ya Japan praising the president. But the President was not pleased with Kamaru's support for multiparty democracy in the late 1980s.
- Rough Guide to the World Music
- Eastafricanmusic.com: The Music Business in Kenya
- Daily Nation, Lifestyle Magazine, April 18, 2009: The memoirs of a musical maverick
- Kimani Njogu & Hervé Maupeu (2007): Songs and Politics in Eastern Africa
- Allmusic profile
- Daily Nation, July 7, 2006: My Take - Joseph Kamaru
- East African, January 27, 2003: Kenyan Music Stays 'Unbwogable' in Hard Times at the Wayback Machine (archived February 27, 2003)