Williams, who graduated from Auburn University with a Bachelor of Science in Design Technology in 1954, served in the rank of Major as a test pilot in the United States Marine Corps.
Williams competed at NASA and was presented on October 17, 1963 along with 13 others as the third group of NASA astronauts to the public. His training began in February 1964. Among other things, he was responsible for the instrumentation of the capsules as well as for safety equipment.
His first assignment for a space flight, he received in June 1965 as a speaker connection ( Capcom ) for the Gemini 4 mission, during Edward White made the first American spacewalk.
On March 21, 1966, he was nominated as a replacement pilot for the Gemini 10 space flight, which took place in June this year. If Michael Collins failed, Williams would therefore have taken the third American spacewalk.
For the flight of Gemini 11 in September 1966, Williams was speaker connection again.
After Williams was assigned to the Apollo program and trained as a pilot of the lunar module. On 22 December 1966, NASA announced the planned crew of the second and third Apollo flight known that ran under the names provisionally Mission D and E mission. Williams made this along with Charles Conrad and Richard Gordon, the backup crew of Mission E. All plans were laid after the disaster of Apollo 1 on January 27, 1967 ice.
Williams died in a plane crash, as the control of its T-38 stopped responding. He was buried at Arlington National Cemetery. Williams is survived by his wife Jane and his daughter Catherine. The second daughter, Jane Dee, was born after his death.
His place in the team of Charles Conrad, Alan Bean took over. Conrad, Gordon and Bean were later backup crew of Apollo 9 and led in November 1969 with Apollo 12, the second lunar landing by. On her mission insignia they had four star set: three for the crew members, the fourth for Clifton Williams.