"His life was filled with love of God, his family and his country," noted wife Betty Ford.
In a message from the White House, President George W Bush said he was "greatly saddened" at the news.
"With his quiet integrity, commonsense and kind instincts, President Ford helped heal our land and restore public confidence in the presidency," Mr Bush said.
"Our 38th president will always have a special place in our nation's memory."
President Reagan's wife Nancy also paid tribute to a "dear friend and close political ally".
"His accomplishments and devotion to our country are vast, and even long after he left the presidency he made it a point to speak out on issues important to us all."
Gerald Ford was born in Omaha, Nebraska, and lived with Betty, 88, at Rancho Mirage, about 130 miles (210km) east of Los Angeles in southern California.
The former president suffered ill health this year and he was taken to hospital four times for tests and angioplasty. He suffered a stroke in 2000.
A statement from Betty Ford said: "My family joins me in sharing the difficult news that Gerald Ford, our beloved husband, father, grandfather and great-grandfather, has passed away at 93 years of age."
The statement did not give the cause of death.
As the only US president never to win a national election, Ford was chosen as Richard Nixon's vice-president in 1973, when Spiro Agnew resigned amid corruption charges.
He then succeeded to the top office when Nixon became embroiled in Watergate - the scandal over a break-in at the offices of the rival Democratic party in Washington in 1972.
Wife Betty became a national figure in her own right, crusading against drug and alcohol addiction.
Following his stroke, Gerald Ford slipped further from the limelight. However, he did join Jimmy Carter, George Bush Snr and Bill Clinton at a memorial shortly after the 11 September attacks in 2001. He was also at the funeral of Ronald Reagan in June 2004.
