Boesch died peacefully Friday night in hospice care in Virginia Beach, Va., surrounded by loved ones, said Steve Gonzalez, director of operations for the SEAL Veterans Foundation.
"He was a legend in the SEAL teams long before 'Survivor,'" Gonzalez said. "Rudy was beloved by all and will be deeply missed."
Boesch was part of the debut cast of "Survivor" in 2000, coming in third place. At 72 years old, Boesch was the oldest contestant ever on the CBS show. He proved so popular as a no-nonsense but loveable character that he was invited back for the eighth season, "Survivor: All Stars."
He and fellow contestant Richard Hatch -- who went on to win the inaugural season -- became friends and formed an alliance.
Hatch acknowledged an "interesting bond" with "Dear Rudy" on Saturday.
"You and I helped open minds and undermine prejudices," he tweeted. "While your time here has passed, you will remain loved and iconic, dear friend!"
Another "Survivor" contestant, Jonny Fairplay, acknowledged Boesch's death and tweeted about the "legend" on Saturday.
Boesch joined the Navy in 1944 and became one of the first SEALs in 1962. He served two combat tours during the Vietnam War, earning a Bronze Star for heroism, and retired from the Navy in 1990 as a master chief petty officer.
Before his retirement, Boesch was honored as "Chief SEAL," or "Bullfrog." The title marks his time as the longest-serving SEAL still on active duty. He remained involved after he left the Navy, serving on the board of directors of the UDT SEAL Association.
Boesch's wife of 53 years, Marjorie Thomas, died in 2008. They have three daughters. Funeral arrangements were not immediately announced Saturday.
The Associated Press contributed to this report.