Frontiere had been hospitalized for breast cancer for several months, the Rams said in a statement posted on their Web site.
"Georgia Frontiere was the first lady of sports in her native St. Louis," NFL commissioner Roger Goodell said in a statement that also praised her philanthropy and concern for retired NFL players.
"Our mom was dedicated to being more than the owner of a football team," daughter Lucia Rodriguez and son Chip Rosenbloom said in the team's statement.
"She loved the Rams' players, coaches, and staff. The warmth and generosity she exuded will never be forgotten."
The one-time nightclub singer was married seven times, starting at age 15. Her sixth husband, Carroll Rosenbloom, owned the Los Angeles Rams at the time of his drowning death in 1979.
The Rams moved twice under Frontiere's leadership, first relocating from the historic Los Angeles Memorial Coliseum in 1980 to Anaheim, 35 miles away.
St. Louis' original NFL franchise, the Cardinals, had left for Arizona in 1988. After the city failed to land an expansion team, civic leaders built a $260 million, taxpayer-financed domed stadium anyway, in hopes of luring another team.
Frontiere, born in St. Louis, agreed in January 1995 to move, causing her to be demonized in Southern California but heralded in her hometown. At a downtown rally soon after the move was announced, thousands chanted "Georgia! Georgia!"
"You take my breath away," Frontiere told the crowd. "It's so good to be back in St. Louis, my hometown."
The Rams won the Super Bowl in 2000.
John Shaw, president of the Rams, said Frontiere was a "loyal, generous, and supportive owner who was totally committed" to the team.
"This is an enormous loss for me and for the Rams' organization. All of our prayers and sympathy go out to her family," Shaw said.
The Rams were the first major sports team to arrive in California when then they moved from Cleveland in 1946. They became the first football or baseball team to leave the state with the move to St. Louis.
Frontiere was a fixture at Rams games during the heyday of the "Greatest Show on Turf" teams that made the playoffs five out of six seasons from 1999 through 2004. Led by quarterback Kurt Warner, running back Marshall Faulk and receivers Isaac Bruce and Torry Holt, the Rams won the 2000 Super Bowl 23-16 and lost the Super Bowl two seasons later on a last-second field goal.