Sully comes from a French surname and place-name, later used as an English nickname-style given name.
Sully arrives primarily from the Irish surname tradition, as a shortened form of Sullivan — anglicized from the Gaelic "Ó Súilleabháin," meaning "descendant of the dark-eyed one" (from "súil," eye, and "dubh," dark). The O'Sullivan clan was one of the great dynasties of Munster, ruling vast territories in Cork and Kerry. After the Cromwellian conquest, the name scattered across the diaspora, taking root in America, Australia, and wherever the Irish went.
As a standalone given name, Sully draws on all of that tenacious Irish energy — compact, warm, slightly rough around the edges in the best way. The name gained modern cultural prominence through two very different figures. Captain Chesley "Sully" Sullenberger became a household name in 2009 after successfully landing US Airways Flight 1549 on the Hudson River, saving all 155 people aboard — a story later immortalized in Clint Eastwood's 2016 film "Sully."
The name also belongs to James P. Sullivan — "Sully" — the beloved blue monster of Pixar's "Monsters, Inc." franchise, giving the name a warmth and gentle humor in the popular imagination.
As a given name rather than nickname, Sully has grown steadily since the 2010s, appealing to parents who want an Irish-flavored name without the ubiquity of Liam or Sean. It is friendly, approachable, and strong without being severe — a name that wears well at every age.