Elected in April 1979, he was the first popularly-elected mayor in the history of Colorado Springs, serving five four-year terms through 1997.

He earned a Bachelor of Science in electrical engineering from the United States Military Academy in 1951 and a Juris Doctor from the University of Southern California's Gould School of Law in 1962.

[1][2] After graduating from the United States Military Academy, Isaac worked as a math teacher in Germany.

On September 29, 1983, President Ronald Reagan nominated Isaac to be a member of the board of trustees of the Harry S. Truman Scholarship Foundation for a term expiring December 10, 1987, succeeding Washington state legislator Dick King.

The terminal at the Colorado Springs Municipal Airport is also named in his honor.