"She was a blessing and the light of my life". Three years before marrying the former Nancy Barbato, he had landed a 15-minute radio show on local station WAAT.
Nancy Sinatra Junior, Frank and Nancy Senior's daughter, tweeted on Friday that her mother died at 6:02 pm.
As for her relationship with the legendary crooner, Nancy and Frank ended up getting along amicably.
One of the women he had an affair with was the actress Ava Gardner, who he married weeks after the divorce papers went through.
Born Nancy Barbato on March 25, 1917 in Jersey City, she met her future husband in the summer of 1934, while they were holidaying with their families on the Jersey Shore.
She later added: 'Godspeed, Momma and thank you for everything you did for us and for the world, ' alongside a fitting tribute, a link to Frank's hit She's Funny That Way.
Nancy Snr. was the first wife of swing music legend and actor Frank and mother to his three children.
They began their marriage living in a modest apartment in Jersey City, where their two eldest children, Nancy Sinatra Jr. and Frank Sinatra Jr., were born.
When Sinatra eventually became a huge success at the beginning of the 1940's, they went on to move to Los Angeles, where he became a movie star and a famous ladies' man.
She also remained friendly with her ex-husband, who is said to have put in requests over the years for pasta and other Italian food dishes she was known to be an expert at preparing.
The Sinatras separated in 1950 and their divorce was finalised in 1951. Nancy never married again.
Gay Talese, in 1966, wrote there was "no bitterness", and instead, only "great respect and affection" between Frank and Nancy.