Early career At age 18, Aspinall had his first amateur fight. He posted a record of nine wins and no losses as an amateur. All but one of his wins came via knockout or submission. He made his professional debut at MMA Versus UK and later fought at
BAMMA, where he amassed a record of 4 wins and 2 losses. He has also fought at Full Contact Contender in between. However, Pessoa withdrew from the bout citing an injury and was replaced by
Jake Collier, but the event was cancelled due to the
COVID-19 pandemic. Subsequently, the pairing was left intact and took place on July 25 2020, at
UFC on ESPN 14. He won the fight via technical knockout in round one. This win earned him the
Performance of the Night award. Aspinall's second UFC appearance was expected to be against
Serghei Spivac at
UFC Fight Night: Moraes vs. Sandhagen on October 11 2020. However, Spivak withdrew from the bout for undisclosed reasons and he was replaced by promotional newcomer
Alan Baudot. Aspinall won the fight via first-round technical knockout. Aspinall next faced
Andrei Arlovski at
UFC Fight Night: Blaydes vs. Lewis on 20 February 2021. He won the fight via a submission in round two. This win earned him the
Performance of the Night award. Aspinall was expected to face
Sergei Pavlovich on 4 September 2021, at
UFC Fight Night 191. However, Pavlovich was removed from the card in late-August due to alleged
visa issues which restricted his ability to travel and was replaced by
Serghei Spivac. Aspinall won the fight via technical knockout in round one. The win earned Aspinall his third
Performance of the Night bonus award. Aspinall was scheduled to face
Shamil Abdurakhimov on 19 March 2022, at
UFC Fight Night 204. However, on 21 January 2022, it was announced that Aspinall would instead face
Alexander Volkov. Aspinall won the fight via straight armbar submission in round one. With this win, he received the
Performance of the Night award. Aspinall faced
Curtis Blaydes on 23 July 2022, at
UFC Fight Night 208. He lost the fight by technical knockout 15 seconds into the first round after being rendered unable to continue due to a knee injury. After a year off due to his injury, Aspinall returned to face
Marcin Tybura on 22 July 2023, at
UFC Fight Night 224. He won the fight via TKO just over a minute into the first round. With this win, he received his fifth
Performance of the Night bonus award.
UFC Heavyweight Champion On two weeks' notice, Aspinall faced
Sergei Pavlovich for the
Interim UFC Heavyweight Championship on 11 November 2023, at
UFC 295 due to
Jon Jones becoming injured and his fight against
Stipe Miocic being cancelled. He won by first-round knockout in a little over a minute and the victory earned him his sixth
Performance of the Night award. Aspinall defended his interim title against
Curtis Blaydes in a rematch on 27 July 2024 at
UFC 304. He won the fight by knockout one minute into the first round. This fight earned him a $100,000
Performance of the Night award. Aspinall served as the backup fighter for the
UFC Heavyweight Championship bout between then current champion Jon Jones and Stipe Miocic on 16 November 2024 at
UFC 309. At the post-fight press conference of
UFC on ABC: Hill vs. Rountree Jr. on 21 June 2025, UFC CEO
Dana White announced that
UFC Heavyweight Champion Jon Jones (also former
UFC Light Heavyweight Champion) had retired from mixed martial arts competition and that Aspinall was promoted as the new undisputed champion as a result. Aspinall faced former interim champion
Ciryl Gane on 25 October 2025 at
UFC 321. During the first round, Gane poked Aspinall in both of his eyes, rendering Aspinall unable to continue. The fight was declared a
no contest. On 29 December, Aspinall announced he was moving forward with multiple eye surgeries, expected to be completed by mid-January, with no return timeline provided. ==Personal life==