In a statement, his family said:
It is with the deepest sadness that we announce the sudden passing of our beloved husband, father and friend, Frank Gifford. Frank died suddenly this beautiful Sunday morning of natural causes at his Connecticut home. We rejoice in the extraordinary life he was privileged to live, and we feel grateful and blessed to have been loved by such an amazing human being. We ask that our privacy be respected at this difficult time and we thank you for your prayers.
Born in Santa Monica in 1930, Gifford attended the University of Southern California on a football scholarship and went pro after being selected 11th overall in the first round of the 1952 draft.
Gifford played with the New York Giants his entire NFL career, from 1952 to 1964, with several visits to the Pro-Bowl. In 1956 he was league MVP and led the team to a championship (before it was called "The Super Bowl").
The Giants used Gifford at running back, defensive back, wide receiver and on special teams. He went to the Pro Bowl at three different positions. His 5,434 yards receiving were a Giants record for 39 years, until Amani Toomer surpassed him in 2003. His jersey number, 16, was retired by the team in 2000.
"Frank Gifford was an icon of the game, both as a Hall of Fame player for the Giants and Hall of Fame broadcaster for CBS and ABC," NFL Commissioner Roger Goodell said. "Frank's talent and charisma on the field and on the air were important elements in the growth and popularity of the modern NFL."
After his playing career ended, he became a sports commentator, first for CBS and then as a co-host of Monday Night Football from 1971 to 1985.
When he wasn't on the field, Gifford tried to put his movie-star good looks to use in Hollywood, appearing in about a dozen films, most notably the 1959 submarine movie "Up Periscope."
He married Kathie Lee Epstein, current TODAY show host, on October 18, 1986.
On Twitter Sunday afternoon, Kathie Lee posted: "Deeply grateful to all 4 ur outpouring of grace. We r steadfast in our faith & finding comfort in knowing where Frank is. Phillippians 4:13."
That verse states, "I can do all things through Christ, who strengthens me."