Haley was born on August 10, 1897 at 166 F St., Boston, Massachusetts, to Canadian-born (Nova Scotia) parents of Irish descent, John Joseph Haley Sr. and Ellen Curley Haley. His father was a waiter by trade, and later a ship’s steward. He died in the wreck of the schooner Charles A. Briggs at Nahant, Massachusetts on February 1, 1898, when Jack was almost six months old He had one older brother, William Anthony “Bill” Haley, a musician, who died of pneumonia in 1916 at the age of twenty-one after contracting tuberculosis.

Haley was raised Roman Catholic. He was a member of the Good Shepherd Parish and the Catholic Motion Picture Guild in Beverly Hills, California. He married Florence McFadden (1902–1996), a native of Wilkes Barre, Pennsylvania on February 25, 1921; “I met her casually” Jack recalled. “As show people often do, and we became inseparable.” They remained married until his death. Flo Haley opened a successful beauty shop and had many film personalities among her clients. The couple had a son, Jack Haley Jr. (1933–2001), who became a successful film producer, and a daughter, Gloria (1923–2010). In 1974, the younger Haley married entertainer Liza Minnelli, the daughter of his father’s Oz co-star Judy Garland. The marriage ended in divorce in 1979. Jack Haley Jr. died on April 21, 2001. Gloria Haley-Parnassus died on May 1, 2010. His nephew Bob Dornan served as a Republican congressman for California.

Haley returned to musical comedies in the 1940s. Most of his ’40s work was for RKO Radio Pictures. He left the studio in 1947 when he refused to appear in a remake of RKO’s Seven Keys to Baldpate. Phillip Terry took the role. He subsequently went into real estate, taking guest roles in television series over the next couple of decades.

Haley’s last film appearance was in 1977’s New York, New York—in the lavish “Happy Endings” musical number, he played a host who introduces a top Broadway star at an award ceremony, played by his then-daughter-in-law, Liza Minnelli. On April 9, 1979, he appeared at the 51st Academy Awards ceremony with his Oz co-star Ray Bolger to present the award for Best Costume Design. Bolger announced the nominees, Haley the winner. Before he could open the envelope, Bolger asked, “How come you get to read the winner?”, to which Haley replied, “When your son produces the show, you can announce the winner.” Jack Jr. was the show’s producer that year. Haley remained active until a week before his death.

On Friday June 1, 1979, Haley suffered a heart attack. He died on June 6, 1979 at the UCLA Medical Center in Los Angeles at the age of 80. He is buried in Holy Cross Cemetery, Culver City, California.

Haley’s autobiography, Heart of the Tin Man, was published in 2000.