Early career Osbourne made his amateur mixed martial arts debut in 2013, originally starting his training at small gym in
Waukesha, Wisconsin. He made his mixed martial arts debut at NAFC: Explosion in 2015, he submitted Brent Lee via rear-naked choke in the second round, before defeating his next two opponents in David Rhodes and Doug Milbrath. He would then lose his first professional fight against Antonio Sanchez via unanimous decision at RFA 39, Osbourne faced Cory Galloway at Pure Fighting Championships 5, and went on to defeat him via split decision. Osbourne would lose against this time to Jose Luis Calvo via kneebar in the first minute of the bout at United Combat League: Havoc In Hammond 4. Osbourne would win his next three bouts; Seigenald Aurtan Daley Jr in the first round via triangle choke at Pure Fighting Championship 9, Daley Jr for the second time via TKO in round one at Pure FC 10, and finally Kelly Offield in round one via triangle choke at HD MMA 15.
Dana White's Contender Series Osbourne faced Armando Villarreal on July 16, 2019, at
Dana White's Contender Series 20 for a chance at a UFC contract. He won the bout after submitting Villarreal via armbar in the first round, earning a UFC contract in the process.
Ultimate Fighting Championship Osbourne made his UFC debut against
Brian Kelleher at
UFC 246 on January 18, 2020. He lost the fight via a submission in the first round. Osbourne was expected to face
Jerome Rivera at a UFC event on January 30, 2021. The event never materialized and the pairing was canceled. Osbourne was expected to face Denys Bondar in a catchweight bout of 130 pounds on February 6, 2021, at
UFC Fight Night 184. However, Bondar withdrew during fight week due to undisclosed reasons and was replaced by
Jerome Rivera, with their bout taking place at featherweight. Osbourne won the fight via knockout out in round one. Osbourne was expected to face
Amir Albazi on July 17, 2021, at
UFC on ESPN 26. At the weigh-ins, Kape weighed in at 129 pounds, three pounds over the flyweight non-title fight limit. The bout proceeded at catchweight and Kape was fined 20% of his purse, which went to Osbourne. He lost the fight via knockout in round one. Osbourne faced
C.J. Vergara on November 6, 2021, at
UFC 268. At the weigh-ins, Vergara weighed in at 127.4 pounds, 1.4 pounds over the flyweight non-title fight limit. The bout proceeded at a catchweight and he forfeited 20% of his purse to Osbourne. Osbourne won the fight via unanimous decision. Osbourne faced
Zarrukh Adashev on June 4, 2022, at
UFC Fight Night 207. He won the fight via knockout in the first round. This win earned him the
Performance of the Night award. Osbourne faced
Tyson Nam on August 13, 2022 at
UFC on ESPN 41. He lost the fight via knockout in round one. Osbourne was scheduled to face Denys Bondar on February 25, 2023, at
UFC Fight Night 220. However, Bondar withdrew from the event for undisclosed reasons and he was replaced by
Charles Johnson. Osbourne won the fight via split decision. Osbourne next faced promotional newcomer
Asu Almabayev at
UFC on ESPN 50 on August 5, 2023. He lost the fight via a rear-naked choke submission in the second round. Osbourne faced Jafel Filho on March 16, 2024, at
UFC Fight Night 239. He lost via rear-naked choke submission at the end of the first round. Osbourne faced
Ronaldo Rodríguez on September 14, 2024 at
UFC 306. He won the fight by technical knockout in the second round. This fight earned him another
Performance of the Night award. Replacing
Park Hyun-sung, Osbourne stepped in on short notice to face former
UFC Flyweight Championship challenger
Steve Erceg in a bantamweight bout on August 9, 2025, at
UFC on ESPN 72. He lost the fight by unanimous decision. Osbourne faced Alibi Idiris on February 21, 2026 at
UFC Fight Night 267. The bout was originally a unanimous decision (29–28, 30–27, 30–27) win for Idiris.. However, on March 31, 2026, it was reported that the result was overturned to a no contest after Idiris tested positive for
hydrochlorothiazide. ==Championships and accomplishments==