Edward (Ed) Scheidt was born in 1939 in California. His father worked for the government, and his mother was a switchboard operator at AT&T. He graduated in 1957 from Cor Jesu High School in New Orleans. He also received a B.A. in computer science from the University of Maryland in 1970, and a degree in telecommunications from George Washington University in 1975. He worked for 26 years at the U.S. Central Intelligence Agency, working primarily in operations, and retired in December 1989.

He is best known for his involvement with part IV of Kryptos (K4), one of the world's most famous unsolved codes. When the CIA commissioned a new Headquarters building in 1988, the commission for some of the associated artwork was awarded to James Sanborn, a Washington DC sculptor who had created some other large public art probjects. After Sanborn researched the themes he wanted to portray in his art, he decided he wanted to incorporate some encrypted messages. Up until that point, Sanborn had never used encryption or text in his work, so he was teamed with Scheidt, who was in the process of retiring. CIA Director William H. Webster referred to Scheidt as "The Deep Throat of Codes".

In a series of discussions, Scheidt taught various encryption methods to Sanborn, and then Sanborn chose the exact messages to be encrypted. Of the messages on the sculpture, three have been solved, but the fourth section, 97 or 98 characters at the very bottom, remains uncracked. Scheidt said that he does know the answer, along with Sanborn and "probably someone at the CIA".

After retiring from the CIA, Scheidt helped found an encryption company called TecSec Inc., in 1990 in Vienna, Virginia, where he presently works as Chief Scientist. One of their first ventures was to manufacture portable satellite versions of the secure "STU-III" telephones used by the government. Scheidt manufactured the first model in his home basement workshop, and as of 2002, approximately 500 were in use world-wide by the United States Foreign Service.

Scheidt has been a speaker on cryptography at Bouchercon, a mystery convention. He also volunteers as a local scoutmaster.