Morriss M. Henry was born in Cincinnati, Ohio in 1931. He attended Hendrix College in Conway (Faulkner County) and received a Bachelor of Science degree in 1952. Three years later he graduated from the University of Tennessee with a medical degree. Henry trained as an eye specialist at Harvard University and later became head of the Eye Clinic in Bitburg, Germany, while serving in the U.S. Air Force from 1959-1961. After Henry returned to civilian life, he opened an opthalmology clinic in Fayetteville.

Henry began his political career in 1964 when he was elected Washington County coroner. He served for two years and then successfully ran for the Arkansas House of Representatives, serving from 1967-1971. He received his J.D. degree in 1971 from the University of Arkansas and was elected to the Arkansas State Senate that same year, where he remained until his retirement in 1985. Throughout those years, Henry continued his eye clinic in Fayetteville and served as president of the Arkansas Medical Society from 1982-1983.

As a member of the House of Representatives, Henry was a member of the Memorials and Resolutions, State Agencies, Public Welfare, Agriculture, Constitutional Amendments, and Labor committees, and served as Vice-Chairman of the Public Health Committee. During his senate years, he served on the Public Health, Welfare and Labor Committee, City, County, and Local Affairs Committee, and was chairman of the Aging and Legislative Affairs committee.

Henry helped secure legislative approval for the state to purchase the 12,000-acre Hobbs Estate, located south of Beaver Lake, as well as the sixty-five acre Borden property for the Prairie Grove Battlefield State Park. He was also instrumental in setting up state regulations for Emergency Medical Services and sponsoring research funds for improvements in Arkansas wastewater treatment.