|Debut||9th March 2012|
|Season 1 Record||1-5|
|Season 2 Record||4-3|
|Season 3 Record||15-18|
|Season 4 Record||13-18|
Sheamus made his WTX Universe debut on the March 9th 2012 edition of SmackDown, attempting to form a team with Drew McIntyre by interfering in his match and attacking McIntyre's opponent, The Undertaker. McIntyre instead of taking the pin when handed to him, hit Sheamus with a Future Shock DDT and accepted the DQ loss as Sheamus' fault.
Despite barely being on any shows Sheamus was voted into an Elimination Fatal 4-Way Intercontinental Championship Match at Over The Limit alongside Brock Lesnar, champion Randy Orton and winner of the match, Wade Barrett.
NXT Champion (2013-2014)
On October 2nd, Sheamus won a championship scramble for the recently vacated NXT Championship. The following week, Sheamus, alongside NXT Tag Team Champions Wade Barrett & Drew McIntyre beat down Ted DiBiase Jr. backstage, they three then assaulted Triple H following a match between Sheamus & Triple H.
At Over The Limit, Sheamus retained the NXT Championship against Samoa Joe despite interference from NXT General Manager Ted DiBiase. At Hell in a Cell, DiBiase faced Sheamus for the championship inside Hell in a Cell, defeating Sheamus for the championship. At Survivor Series, Sheamus defeated DiBiase in a rematch to reclaim the NXT Championship. At TLC: Tables, Ladders & Chairs, Sheamus was challenged by DiBiase's enforced Andre the Giant in Andre's debut match, Sheamus won the Table Match, throwing Andre through a table with a Fallaway Slam. At Royal Rumble, Sheamus retained his championship against both Shawn Michaels & Ted DiBiase Jr. when DiBiase assisted Sheamus in retaining the championship, which was revealed to be DiBiase rebelling against his father, who had pushed him into the match despite injuries. On the January 22nd edition of NXT, Sheamus was put into a match with his United Kingdom allies, as well as Ted DiBiase Jr. and a mystery opponent revealed to be Shawn Michaels, Michaels won the match, defeating Sheamus for the NXT Championship. At No Way Out, Sheamus competed again for the NXT Championship, making it to the end only to be eliminated by Diesel after a Knockout Punch.
As WrestleMania III drew near, The United Kingdom split into two teams, with William Regal & Adrian Neville remaining a team and Drew McIntyre & Sheamus going their seperate ways as The Celtic Cross, the two faced off at WrestleMania III, with The United Kingdom retaining the NXT Tag Team Championship. The match had intitally added the stipulation that if Celtic Cross had won, McIntyre would remain on NXT, however if he lost, he would be drafted to RAW, making the original run only one night.
On November 19th, Sheamus reunited with McIntyre to defeat the team of Big E & Alberto Del Rio, qualifying both for Team NXT at Survivor Series. At Survivor Series, Team NXT lost to Team RAW, when Sheamus was pinned last by Team RAW's Ethan Carter III.
On December 3rd, Sheamus defeated McIntyre to qualify for the NXT Championship Elimination Chamber at NXT Arrival. At NXT Arrival, Sheamus was unable to win back the NXT Championship, being eliminated fourth by the match by Batista.
Draft to RAW (2015)
In April of 2015, Sheamus was drafted from NXT to RAW as part of the 2015 Supplemental Draft. At Over the Limit, Sheamus faced Drew McIntyre, who he betrayed on an episode of RAW heading into the event, Sheamus then went on to defeat McIntyre. At SummerSlam, Sheamus then challenged for the WWE Championship, losing to the champion Ryback in the main event. At Cyber Sunday, Sheamus competed for the WWE Championship, losing to the champion Bobby Roode. At Night of Champions, Sheamus issued an open challenge, defeating Kurt Angle.
At Vengeance, Sheamus competed in an Elimination Chamber match for the WWE Championship, being eliminated first by The Undertaker.
Celtic Cross Reunion (2016)
Throughout 2016, Sheamus found himself on the losing end of most matches, being booked a lot more sparingly at the start of the year. On April 18th, Sheamus got an opportunity to face The Undertaker on Raw, picking up a huge upset victory after sustaining minor injuries at the hands of Undertaker in the match. Baron Corbin, who was rivaling with Undertaker, claimed that he was responsible to Sheamus' victory. On the May 2nd edition of Raw, Corbin challenged Sheamus to prove his point, Corbin defeated Sheamus with his End of Days finisher. Sheamus then returned to tag team competition, entering himself in the Joker's Wild Tournament, he was randomly paired with former partner Drew Galloway, temporarily reforming Celtic Cross. The former team defeated Mark Henry & The Miz on May 9th to advance in the tournament. The team would then be eliminated from the tournament by Drago & Joey Ryan on June 6th, however, they stated that they would stick together as a team.
On April 2nd 2017, Sheamus was drafted from RAW to ECW as part of the 2017 Draft.