Born Leo Anthony Gallagher Jr., he died of organ failure in hospice care in Palm Springs, California, TMZ reports.
Gallagher shot to fame in the 1970s after appearing on late-night television shows, including “The Tonight Show Starring Johnny Carson.”
He then gained more prominence through 13 specials, beginning with 1980’s “An Uncensored Evening” for Showtime, which was the network’s first comedy special, Variety reported.
He also recorded several comedy specials for HBO.
Even after the height of his fame, Gallagher’s influence persisted through homages and parodies, including in the early 2000s on “Chapelle’s Show,” which captured his trademark smashing of watermelons and other items using his “Sledge-O-Matic” hammer.
In recent years, however, Gallagher’s act was criticized by some as being homophobic and racist. He notably stormed out of a recording of the “WTF with Marc Maron” podcast mid-interview when questioned about some of those jokes.
He also sued his younger brother, Ron, for trademark infringement after he adopted the moniker Gallagher II and went on tour “mimicking his act,” the Tampa Bay Times reported.
On his Facebook page, Gallagher promoted performances from as recently as October, noting that he was “feeling great!!” and wanted to work on “projects to make this world a ‘funner planet.’”