Thomas was born in 1947 in the small west Texas town of Haskell. When he was three years old, the family moved to Midland, Texas, where he attended public schools through the eighth grade. In 1961 the family moved to Brownwood, Texas, where he attended Brownwood High School, graduating in 1965 as a member of the National Honor Society.

After graduation from high school, he attended Howard Payne University in Brownwood for two years, supporting himself by working afternoons, evenings and weekends as a district circulation manager for The Brownwood Bulletin newspaper. He transferred to the University of Houston in 1967, attending night classes on a full-time basis until he graduated in 1970 with a B. A. degree in English literature. While attending the University of Houston, he supported himself through his full-time employment as a district caseworker for the Harris County Social Services Department.

He completed a four-year tour of duty in the U. S. Navy immediately after receiving his bachelor’s degree, serving as a correctional counselor in the Navy Correctional Center, Norfolk, Virginia. During his naval service, he started writing poetry consistently on weekends, a disciplined practice he would maintain throughout his twenty-three year, post-naval career in the adult probation field. By the time he retired as a branch director of the Harris County Community Supervision and Corrections Department (in Houston) in 1998, he had published a large number of poems in numerous national literary journals.

In January 2001, he brought out his first collection of poetry, The Lighthouse Keeper, with Timberline Press (Fulton, MO), a handset letterpress edition illustrated with original linocuts and a serigraph. He was awarded the 2001 Texas Review Poetry Prize for Amazing Grace. The volume also won the 2003 Western Heritage Wrangler Award, a national award for a book of poems celebrating the historical or contemporary American West, and was a Spur Award finalist. His subsequent volumes of verse received several significant prizes and awards, including the 2004 Texas Review Poetry Prize and 2004 Violet Crown Award (both won by Where Skulls Speak Wind, Texas Review Press 2004); three Pushcart Prize nominations; four additional Spur Award finalist citations; and a Poets' Prize nomination (West Chester University). In April 2007, Larry was appointed by the Texas Legislature as the 2008 Texas Poet Laureate. He was inducted into the Texas Institute of Letters in April 2009.