Jim Jefferies was born Geoffrey James Nugent on February 14, 1977, in Sydney, Australia. He won a scholarship to the prestigious Western Australian Academy of Performing Arts (WAAPA) in Perth, where he studied musical theatre and classical music. However, he left before graduating, returning to Sydney and pivoting to stand-up comedy before relocating to the United Kingdom, where he built a strong following on the club circuit throughout the early 2000s.

His international breakthrough came in 2009, when his first HBO special, I Swear to God, introduced him to American audiences. From there, he launched the FX sitcom Legit in 2013, which he co-wrote, executive-produced, and starred in. Subsequently, in 2017, he co-created and hosted The Jim Jefferies Show on Comedy Central, which ran for three seasons.

Today, Jefferies hosts the hit Australian game show The 1% Club on the Seven Network and The Snake on Fox/Hulu in the US. He has also released ten stand-up specials, most recently Two Limb Policy on Netflix in 2025. On a personal note, he married English actress Tasie Lawrence in September 2020. He has two sons — Hank, from a previous relationship, and Charlie, with Lawrence.