Frehley died peacefully surrounded by family in Morristown, New Jersey, following a recent fall, according to his agent.
Family members said in a statement that they are "completely devastated and heartbroken" but will cherish his laughter and celebrate the kindness he bestowed upon others.
KISS, whose hits included "Rock and Roll All Nite" and "Detroit Rock City," was known for its theatrical stage shows, with fireworks, smoking instruments and fake blood spewing from the mouths of band members in body armour, platform boots, wigs and signature black-and-white face paint.
Bandmembers took on the personas of comic book-style characters — Frehley was known as "Space Ace" and the "Spaceman."
"We are devastated by the passing of Ace Frehley," Gene Simmons and Paul Stanley said in a joint statement.
"He was an essential and irreplaceable rock soldier during some of the most formative foundational chapters of the band and its history. He is and will always be a part of KISS's legacy."
The band was extremely popular, especially in the mid-1970s, selling tens of millions of albums and licensing its iconic look to sell numerous products.
Frehley and his bandmates were inducted into the Rock and Roll Hall of Fame in 2014.
Frehley left the band in 1982, skipping the years when they took off the makeup and had mixed success. He performed both as a solo artist and with his band, Frehley's Comet.
But he rejoined KISS in the mid-1990s for a triumphant reunion and restoration of their original style that came after bands including Nirvana, Weezer and the Melvins had expressed their affection for the band and paid them musical tributes.
Frehley's is the first death among the four founding members, a group that also includes singer-guitarist Stanley, Gene Simmons and drummer Peter Criss.
