Having begun his career on the independent circuit in 2002 as Shawn Spears, Arneill initially joined WWE in 2006 and worked for the company between 2006 and 2009, performing in the developmental territories Ohio Valley Wrestling (OVW) and Florida Championship Wrestling (FCW) as well as briefly on the main roster brand ECW under the slightly modified ring name Gavin Spears.

After a rise in popularity, he was promoted to the main roster in April 2017, working on the SmackDown brand until his second release from the company in February 2019.

Shortly after leaving WWE, he signed with the newly founded AEW in May 2019, reverting to his Shawn Spears name.

After his AEW contract expired at the end of 2023, Arneill rejoined WWE in February 2024 and was assigned once more to the NXT brand, retaining the Shawn Spears character.

On February 27, 2005, Arneill made an appearance on an edition of WWE Heat, unsuccessfully teaming with Mikael Yamaha to face The Hurricane and Rosey.

After sending a tape to World Wrestling Entertainment (WWE) officials, Arneill was called for a try-out in Buffalo, New York.

[1] After signing his WWE contract, Arneill was assigned to the company's developmental territory, Ohio Valley Wrestling (OVW).

Spears then began feuding with Runnels and eventually lost the OVW Television Championship to him on July 6, 2007 before winning it back one week later.

Spears then began feuding with Cabana and the pair went on to win the vacant OVW Southern Tag Team Championship with on November 7 after defeating Paul Burchill and Stu Sanders.

On December 19, Cabana and Spears' feud culminated in a ladder match in which the winner would claim the OVW Southern Tag Team Championship for themselves and choose a new partner.

[10] After a three-month absence due to competing in FCW, Spears returned to television on the December 16 episode of ECW, where he lost to Finlay in what turned out to be his final match for the company.

The team of Dillinger and Jordan got their first televised win on the April 17 episode of NXT, defeating Baron Corbin and Sawyer Fulton.

On the December 14 episode of NXT, Dillinger defeated Eric Young by disqualification in a number one contender's Fatal 4-Way qualifying match.

At NXT TakeOver: San Antonio, Dillinger was defeated by Young following a distraction from Alexander Wolfe and Killian Dain.

Dillinger made his last NXT appearance on the April 5 tapings, closing out the event by winning a Steel Cage match against Eric Young.

[21] On the April 4 episode of SmackDown Live, Dillinger made his main roster debut, defeating Curt Hawkins.

[23] On the July 4 episode of SmackDown Live, Dillinger competed in an Independence Day Battle Royal to determine the number one contender to the United States Championship, lasting until the final three before being eliminated by Sami Zayn.

[25] On the August 29 episode of SmackDown Live, Dillinger confronted and brawled with Baron Corbin, who was about to answer an open challenge set by AJ Styles for the United States Championship.

[31] At WrestleMania 34, Dillinger competed in the André the Giant Memorial Battle Royal, where he was eliminated by Matt Hardy.

[32] In his final pay-per-view appearance, Dillinger competed in the Greatest Royal Rumble, where he entered at number 42, but was quickly eliminated by Braun Strowman.

[38] On the June 5 episode of Beyond Wrestling's weekly show, Spears debuted for the promotion defeating Orange Cassidy in the main event.

[39] Arneill, under his previous name of Shawn Spears, debuted for All Elite Wrestling (AEW) at their inaugural pay-per-view event Double or Nothing, competing in the pre-show Casino Battle Royale that Adam Page won.

[42] At Fyter Fest in June, Spears established himself as a heel after hitting Cody with a steel chair shot to the top of the head.

He then presented him with a black glove, similar to the one worn by Blackjack Mulligan and Ted DiBiase, that can be illegally loaded with a metal slug.

Spears lost to Wardlow on the May 25 episode of Dynamite in a steel cage match, with MJF as special guest referee.

Spears returned on the October 12 episode of Dynamite in Toronto as a face, reverting to his "Perfect 10" gimmick from WWE.

Arneill made his return to WWE in the February 27 episode of NXT, attacking Ridge Holland with a steel chair.

[62][63][64] In August 2019, Arneill married Australian professional wrestler Cassandra McIntosh, best known by her ring name Cassie Lee in Impact Wrestling and as Peyton Royce in WWE.

[70] On December 24, 2023, he and McIntosh announced they are expecting their second child, also a boy, Harley Dean Arneill who was born on June 21, 2024.