Edward Aubrey Clark was born San Augustine, Texas on 15th July, 1906. He obtained his first degree from Tulane University in New Orleans. In 1927 Clark married Anne Metcalfe of Greenville, Mississippi, and heir to the largest cotton plantation system in the South.
Clark received a law degree in 1928 from the University of Texas. After leaving law school, Clark became a county attorney in San Augustine. In 1932 he moved to Austin and served as assistant attorney general of Texas.
In 1935 Clark became assistant to Governor James Allred. Soon after he met Lyndon B. Johnson and the two men became close friends. The governor appointed Clark secretary of state in 1937. The following year Clark opened a private law practice with Everett Looney. He also worked as a political lobbyist for the oil industry. One of his main clients was Big Oil, a company owned by Clint Murchison and Wofford Cain. He was also a member of the Texas Guard.
After Pearl Harbor he joined the United States Army. During the Second World War he served as a captain in the quartermaster corps. In January, 1943, he was expelled from the service for mishandling army funds. Clark now returned to Austin. In 1944 Clark recruited Don Thomas and his company became known as Clark, Thomas and Winters. Over the next few years it became one of the most influential and successful firms in Texas. Clark also served as chairman of Texas Commerce Bank of Austin and the First National Bank of San Augustine.
In 1948 Clark was appointed as Lyndon Johnson's legal counsel. He remained active in the Democratic Party and was associated with those opposed to the liberal elements led by Ralph Yarborough. After the assassination of John F. Kennedy Johnson became president. In 1965 Johnson appointed Clark as the country's ambassador to Australia.
Clark opposed the Democratic Party policy on civil rights and in the 1968 presidential campaign he supported Richard Nixon over George McGovern. In 1974 Nixon appointed Clark to the General Advisory Committee of the United States Arms Control and Disarmament Agency. Later he supported Ronald Reagan in his campaign to become president.
Edward Aubrey Clark died of lung cancer in Austin on 16th September 16, 1992. Clark donated his 7,000 books on the history of Texas to Southwestern University.
In 2003 Barr McClellan, Clark's former legal partner, published Blood, Money & Power: How LBJ Killed JFK. In the book McClellan argues that Clark and Lyndon B. Johnson were involved in the planning and cover-up of the assassination of John F. Kennedy. As Nigel Turner has pointed out: "His arch villain is Texan attorney Edward A Clark. He controlled LBJ's financial, legal and political fortunes for three decades from offices in downtown Austin. He accuses Clark, now deceased, of being the man who personally orchestrated the assassination of JFK when Johnson faced political ruin and possible imprisonment due to past misdeeds."