The son and grandson of wallpaper wholesalers, Denny was born in Baltimore, Maryland and grew up in Washington, D.C.
He married Elizabeth Woolsey on December 31, 1937; the couple had three children: Alison, Christine, and Charles.
He left the FCC on October 31, 1947, and was succeeded as chairman on an interim basis by commissioner Paul A. Walker.
Wayne Coy was appointed to the remainder of Denny's term, and was designated chairman when he took office.
On leaving the commission, Denny took a position as general counsel of NBC; he later rose to executive vice-president of parent company RCA.