After debuting on ECW in June 2009 and feuding with Goldust, Sheamus was drafted to Monday Night Raw in October 2009 where he garnered attention for attacking the ring crew and retiring Jamie Noble in a vicious post-match assault. The Miz led Sheamus, Drew McInyre, and others to victory at Survivor Series where Sheamus logged the winning pinfall over John Morrison.
The following night, Sheamus won a "break-through" battle royal, which Jesse Ventura held exclusively amongst men who had never won a world championship. A few weeks later, Sheamus upset John Cena to win the WWE Championship, making him the first Ireland-born WWE Champion. Sheamus lost the championship two months later at Elimination Chamber when Triple H pinned him. The two faced off in a singles match at WrestleMania XXVI, which HHH won. Sheamus won a Street Fight the following month and hospitalized Hunter. Afterwards, Sheamus regained the WWE Championship on June 20, 2010, admist interference by the Nexus. Sheamus defeated Cena in a steel cage match at the first Money in the Bank pay-per-view and retained against Randy Orton at SummerSlam before losing the title at Night of Champions in a Six-Pack Challenge.
After that, Sheamus was booked in the upper midcards and main events, feuding with John Morrison, Daniel Bryan, Kofi Kingston, Christian, and Randy Orton, until he won the 2012 Royal Rumble for a WrestleMania title shot, in which he won the World Heavyweight championship belt. He held it for several months (mostly defending against Alberto Del Rio) before dropping the belt to Big Show in October 2012.