Standout achievements
Zac O'Brien is an Australian mixed martial artist with a professional record of 4-5 across 9 bouts. They've won 4 by KO/TKO, 0 by submission and 0 by decision — a 100 % finish rate. Most wins come by KO/TKO. Currently on a 2-fight skid. Last competed June 2026 (active). Has fought most often in Australia (9 bouts).
Fight locations (3 venues)
Career timeline — fights by year
Frequently asked
What is Zac O'Brien's MMA record?
Zac O'Brien has a professional MMA record of 4-5 — 4 wins by KO/TKO, 0 by submission, 0 by decision.
How does Zac O'Brien usually win?
They most often win by KO/TKO (4 of 4 wins).
How does Zac O'Brien usually lose?
Most of Zac O'Brien's losses come by submission (2 of 5).
Is Zac O'Brien still active?
Zac O'Brien last competed in June 2026, and is considered active (no bout in over two years).
What is Zac O'Brien's fastest finish?
KO/TKO of Bailey Rach in 0:14 (Rd 1) at PGFL 6 - Proving Grounds Fight League 6.
Where is Zac O'Brien from?
Zac O'Brien is a Australian mixed martial artist.
What is Zac O'Brien's longest MMA win streak?
Zac O'Brien's longest winning run on record is 2 straight victories.
Where does Zac O'Brien rank in MMA?
Zac O'Brien sits at #23,172 of 32,696 fighters in the Fight Forensics global MMA rankings.