Clark was born to a judge in Massachusetts. He graduated from Dartmouth College, New Hampshire and went on to serve in the United States Navy. While in the Navy he worked as a gunnery officer, and served in the Korean War. After returning from the War he went to Harvard to earn his law degree. Clark became a Harvard graduate in 1957. After his graduation he joined a Wall Street law firm and he specialized in antitrust cases. At the time Clark was a liberal Republican. However, President Nixon’s wage-price freeze in 1971 changed his mind. He says, "That was a great blow to the free market system. I felt betrayed and said, 'Never again.' " With that Clark joined the Libertarian Party.
In 1978, Ed Clark ran for the governor of California. He received about 377,960 votes, or 5.46% of votes. Clark ran as an independent candidate even though he was part of the Libertarian Party. Two factors that may have led to the number of votes that Clark received was the successful passing of Proposition 13—limited property taxes—and the failure of the anti-gay Briggs Initiative. These two issues revealed the type of people who were more likely to vote Libertarian. At the 1979 Libertarian Party presidential nominating convention in Los Angeles, California Clark became the Libertarian candidate for President and David H. Koch was his running mate. Clark proposed tax cuts and a large budget. He reached out to liberal progressives by opposing the resumption of the Selective Service and the arms race with the Soviet Union. During his presidential campaign Clark used the phrase “low-tax liberalism” which caused a rift in the Libertarian Party. It formed two factions within the Party: the moderate faction led by Ed Crane and the radical faction led by Murray Rothbard. After David Bergland won the nomination for the Libertarian Party’s candidate for the presidential race, the moderate faction left the Libertarian Party. Clark and Koch gained 921,128 (1.06% of the total votes). It was nearly a million votes and it was the highest amount of votes that any Libertarian candidate had ever gained in a presidential election before.