Yami Lester was born at a place called Wallatina, in northern South Australia. His wapar, dreaming, is the ngintaka. Lester has been a strong advocate for his people.
Lester was nearly eleven when he started his first job minding goats at Cullinan Station. His family lived at Wallatina, at the time of the Maralinga bomb tests; shortly after the explosions Lester lost sight in one eye. He learned how to muster, brand and castrate cattle, but a few years later his remaining eye began to lose vision also. In 1956, Lester was sent to Adelaide where he had an operation to remove his second eye.
Lester was sent to Colebrook Children's Home in Adelaide, where he lived for four and a half years. While at Colebrook he started working at the Institute for the Blind, making brooms and paint brushes, and he worked there for thirteen years, before doing interpreting work in the Pitjantjatjara language. In 1970, Lester moved to Alice Springs to work as an Interpretor with Jim Dowling and Indigenous Australians living in Alice Springs. He also worked as a consultant for the Institute of Aboriginal Development (IAD) for several years before moving to Mimili, South Australia, in 1975.
In Mimili, Lester managed the Mimili Cattle Company, where he turned the company's finances around and got it making a profit for the community. Once this was done he moved back to Alice Springs to work for IAD again. By 1980, Lester was the Director of IAD, a position he held for six years.
Active within his community, Lester was nominated the Mimili, Fregon and Indulkana representative on the Pitjantjatjara council. He was involved with meetings for land rights on Anangu lands in Central Australia. Lester was a part of a delegation that travelled to Adelaide to discuss mining on Granite Downs with the South Australian Government. As a result of this delegation's discussions, the Pitjantjatjara Land Rights Act and the Anangu Pitjantjatara Lands (AP Lands) were established. Lester was also involved in the negotiations surrounding Uluru's land lease.