Liddy was a key, perhaps the key member of the White House "plumbers" unit, which had been created to "fix leaks" to the media. With E. Howard Hunt, he planned and coordinated the first break-in of the Democratic National Committee headquarters in the Watergate building in 1972. He was convicted of conspiracy, burglary and illegal wiretapping, and sentenced to 20 years, serving five and a half before his sentence was commuted by Jimmy Carter.
Unlike many of the other conspirators, when he was busted, Liddy didn't rat out his colleagues and in part for that reason received a stiffer sentence.

Before the scandal, Liddy had been an FBI agent, with a reputation of a cowboy, before leaving the Bureau to practice law. He worked as a lawyer and prosecutor, once firing a gun into a courtroom ceiling during a jury summation.

After working for the Nixon campaign in 1968, Liddy served in several positions for his administration, before moving to the Committee to Re-elect the President, and specifically to the Plumbers unit. Liddy proposed several ideas, including firebombing the Brookings Institute and entrapping Democrat campaign officials with prostitutes. Most of these schemes were rejected, but his plan to burgle Daniel Ellsburg's psychiatrist got the green light, as did the plan to break into the DNC.

After prison, he published a best selling autobiography, wrote several other books, had a college speaking tour, and a very successful talk radio show. In his autobiography he states that he once made plans with Hunt to kill journalist Jack Anderson, based on a literal interpretation of a Nixon statement "we need to get rid of this Anderson guy"

Liddy was a thug with a law degree, and appears to have been utterly amoral. Unlike some of the key participants Liddy has never recanted or even seriously acknowledged wrongdoing.