[4][5] Aspinall's first European Tour appearance was at the Dutch Darts Masters and he squeezed past Jamie Robinson and Vincent van der Voort both 6–5.

[7] Aspinall won the seventh Development Tour event of 2015 with a 4–2 victory over Benito van de Pas.

[9] Aspinall made his first televised appearance in the final of the 2015 PDC World Youth Championship, where he played the German Max Hopp.

[14] At the sixth Players Championship he reached his first quarter-final on the main tour and narrowly lost 6–5 against Vincent van der Voort.

[16] Aspinall won his first ranking PDC title in September 2018, beating Ryan Searle 6–4 in the final of Players Championship 18, in Barnsley.

[19] Aspinall then defeated Kyle Anderson 4–1,[20] Devon Petersen 4–3[21] and Brendan Dolan 5–1[22] on his way to the semi-finals, where he lost to Michael Smith 6–3.

Aspinall won his first PDC major at the 2019 UK Open, defeating Toni Alcinas, Christian Kist, Madars Razma, Steve Lennon, Ross Smith and Gerwyn Price to reach the final, where he defeated Rob Cross 11–5 to take the title, winning the final leg with a 170 checkout.

[25] In the first round, he defeated Shawn Brenneman 6–2 before achieving wins over Rob Cross 8–5, and Peter Wright 8–7 in a last leg decider.

[28] He was selected for his Premier League Darts debut season as part of the 2020 lineup after competing as a 'contender' the previous year.

[30] He defeated reigning world champion Peter Wright 10–7 in the semi-finals to set up a clash with fellow Premier League debutant Glen Durrant in the final.

[44] At the World Grand Prix in October, Aspinall reached the final following a 4–2 win over Gerwyn Price in the semi-finals, setting up a match against Michael van Gerwen for the prize.

[50] He reached a sole 2023 European Tour final at the German Darts Grand Prix, losing 8–5 to Michael Smith.

[52] He finished the league phase in fifth place, missing out on qualifying for the play-offs by failing to reach the final on night 16.

[54][55] His run to the final included wins over Krzysztof Ratajski, Danny Noppert, Chris Dobey and Joe Cullen.

[57] He made the final of the New Zealand Darts Masters but lost a deciding leg to Rob Cross who won 8–7.

He picked up his first win on night five in Exeter, beating Peter Wright and world champion Luke Humphries before a 6–2 victory over Rob Cross in the final.

[64] Prior to the tournament, Aspinall admitted that due to a tennis elbow-like injury, he would be taking a break following his title defence.

[68] Entering the second round of the 2025 World Championship as 12th seed, Aspinall began his campaign with a 3–1 win over Leonard Gates.

After the match, Aspinall stated that he wanted to prove how good he was and go deep in the tournament after facing scrutiny for recent poor performances.