He did his medical residency in New York Hospital and completed a fellowship in tuberculosis and infectious diseases at Cornell University.
LeMaistre retired in 1996, concluding a distinguished medical career after 18 years as president of the University of Texas MD Anderson Cancer Center.
He was President Emeritus of the University of Texas MD Anderson Cancer Center, and had an active voluntary patient advocacy with his wife Andreae.
He was also chosen Outstanding Texas Leader by the 7th Annual John Ben Sheppard Public Leadership Forum.
He received numerous honorary degrees in recognition of his achievements in medicine, higher education, and public health.