Both of his parents were born in the Russian Empire (presently Poland) and immigrated to the United States in the early 20th century.

After law school, Gildenhorn served in the United States Army and was stationed in Germany.

[3] In 1956, Gildenhorn and high school friends Donald Brown and Gerald Miller founded a law firm.

[3] Gildenhorn served as Chairman of the Board of Trustees of the Woodrow Wilson International Center for Scholars from 2002 to 2013, appointed by George W.

[3] Gildenhorn was a financial supporter of John F. Kennedy Center for the Performing Arts[7] and the Institute for Bone and Joint Health of Sibley Memorial Hospital.