Born in Edinburg, Texas, Keeter graduated from Alamo Heights High School in San Antonio. He earned a B.L.A. from Texas A&M University in 1956. There he was a member of the Texas Aggie Corps of Cadets and later served for a short while as a lieutenant in the U.S. Air Force while stationed in Savannah, Georgia. In 1960 Keeter moved back to San Antonio to practice landscape architecture. His commissions ranged from residential work to civic and corporate projects, all known for their attention to detail and use of local plant materials.
Among his notable projects is the landscape design for the Texas Governor’s Mansion in Austin, and, in 1968, an extension of the San Antonio River Walk from the horseshoe bend to the new convention center and the Tower of the Americas, built for the World’s Fair that year. Keeter’s master plan for the San Antonio Botanical Garden, a landscape which includes various formal display gardens connected by curved pathways, established the location of the Center’s ornamental areas and the arrangement of the planting beds. He also designed the Historic Arkansas Riverwalk in Pueblo, Colorado, and the Riverwalk in Estes Park, also in Colorado. Keeter was named a Fellow of the American Society of Landscape Architects in 1984. He was buried at Greenwood Cemetery in Fredericksburg, Texas, with military honors.