Rover Thomas was born in about 1926 at Gunawaggi, Well 33 on the Canning Stock Route in the Great Sandy Desert of Western Australia. A Kukatja/Wangkajunga speaker, Rover's first father, Lanikan Thomas was Wangkajunga, as was his second father, Sundown: his mother Ngakuyipa (Nita) was Kukatja. From an East Kimberley perspective, Rover Thomas belonged to the Joolama subsection or skin group.

Rover Thomas lived in the bush with his family until his mother died when he was about 10 years old. Then he moved to Billiluna Station where he was initiated into traditional law by a man from Sturt Creek and eventually worked as a jackaroo. As a young man, he worked with a European fencing contractor in Wyndham and later the Northern Territory. After two years, he returned to Western Australia and worked as a stockman on Bow River Station where he married for the first time. Later on, he worked on Texas Downs Station for nine years, before moving to Old Lissadell Station and Mabel Downs Station, and back to Texas Downs where he met his second wife, Rita. Then he worked in Noonkanbah community, before moving to Warmun where he worked as a carpenter's assistant, building new houses in the community.

Shortly after moving to Warmun early in 1975, Rover Thomas found or was given the open ceremony of the Gurirr Gurirr (Kril Kril) which eventually provided a stimulus for the production of art in the East Kimberley. To complement specific verses of the Gurirr Gurirr song cycle, first performed in Warmun in the late 1970s, pieces of plywood were painted with ochre and carried on the shoulders of participants. Rover Thomas and his classificatory uncle Paddy Jaminji painted many of these works on board which were seen by various people including Mary Macha, the Manager of Aboriginal Traditional Arts, Perth who began to market their work in about 1983 –84. A few years later Rover began to paint for Waringarri Aboriginal Arts, Kununurra.