Rubuni was born in Livangula in 1969. He came to Dar es Salaam in 1988 to look for a job and succeeded to get a job as a service man a a house. He quit after one year and wrote a letter to the Tingatinga Cooperative to ask for a position as a painter. His teacher was Mzee Chimwanda. He got married in 1993 and now he is living with his wife and two children in Kawe, north of Dar es Salaam. His paintings were shown on exhibition in Sweden in 2008 (Lilagalerie). His paintings are of high quality work. His paintings of giraffes are very typical.