A prolific visual artist, he started painting and drawing as a boy in Brownsville, Texas in the mid 1940s. He was born in 1937 in Presidio, across the border from Ojinaga and Chihuahua. Robertsons family moved to Brownsville when he was 8. He started drawing and painting soon after. He studied commercial art at Texas Southmost College (now UTB-TSC) and earned a degree in fine arts in 1968.
He later found true inspiration in the colors, flowers and churches of Mexico, where he spent most of his adult life working as an artist. Robertson did nothing but paint, and lived completely off of his art. He would often travel to Brownsville throughout his life to teach free classes for the Brownsville Art League.
In 2002, Nancy Thompson, an old friend of Robertsons, helped establish the Oris Robertson Scholarship Endowment at the University of Texas at Brownsville and Texas Southmost College. The endowment gives local students and professors the chance to follow in Robertsons footsteps by providing funds for them to study, paint and find inspiration in Mexico.
Oris Robertson died of cancer in 2002 at the age of 64.