In the 2009 WWE Supplemental Draft, Natalya and DH Smith were officially drafted to the ECW brand, despite Smith never debuting for SmackDown. On the May 12 episode of ECW on Sci Fi, Smith debuted on ECW under the name David Hart Smith, by interfering in Kidd's match against Finlay, signaling the formation of the group, briefly under the name The Hart Trilogy, before settling on The Hart Dynasty. Smith made his debut with the group by defeating Finlay the following week. The team had their first match together, alongside Jack Swagger, by defeating fellow Canadian Christian and Tommy Dreamer in a handicap match on May 26. They made their first appearance as just a tag team on the June 9 episode of ECW by defeating Christian and Swagger. On June 29, the trio were traded to the SmackDown brand and debuted as a team for the brand on the July 3 episode of SmackDown, when Kidd and Smith lost to Cryme Tyme. The Hart Dynasty made their pay-per-view debut at Bragging Rights in a 14 man tag team match in which their team was successful in winning. They also had their first match for the Unified WWE Tag Team Championship against D-Generation X in December, but lost.
On March 28, 2010, The Hart Dynasty, (along with the rest of the Hart family), were in their uncle Bret's corner as he faced Vince McMahon in a No Holds Barred match at WrestleMania XXVI, performing a Hart Attack on McMahon during the match and officially becoming fan favorites as a result. The following night on Raw, The Hart Dynasty defeated the Unified Tag Team Championship ShoMiz (The Miz and The Big Show) in a non-title match, after ShoMiz had insulted Bret Hart.
At Extreme Rules, they earned a shot at the Unified Tag Team Championship after defeating ShoMiz as part of a tag team gauntlet match (which also included the team of John Morrison and R-Truth and the team of Montel Vontavious Porter and Mark Henry). On the April 26 episode of Raw, The Hart Dynasty defeated ShoMiz to win the Unified Tag Team Championship. The following day, all three members were officially drafted to the Raw brand in the 2010 WWE Supplemental Draft. On May 10, Kidd defeated The Miz in a match which earned any member of The Hart Dynasty a match for The Miz's WWE United States Championship. The Miz was allowed to pick his opponent for the championship match, and he chose to face Bret Hart. On the following episode of Raw on May 17, Hart defeated The Miz to win the United States Championship, with help from the other members of The Hart Dynasty, who prevented Chris Jericho, William Regal, and Vladimir Kozlov from interfering on The Miz's behalf.
On May 24, 2010, Hart was named as the Raw General Manager and vacated the United States Championship as a result. On the same episode of Raw, The Hart Dynasty began a rivalry with a group composed of Jimmy and Jey Uso, the sons of Rikishi, and Tamina, the daughter of Jimmy "Superfly" Snuka. This led to a non-title six-person mixed tag team match at the Fatal 4-Way pay per view, where Natalya pinned Tamina to win the match. The following night on Raw, Hart was fired as General Manager. The following month at the Money in the Bank pay-per-view, The Hart Dynasty and The Usos competed in a tag team match for the Unified Tag Team Championship, which Kidd and Smith won to retain the championship.
On the August 16 episode of Raw, the World Tag Team Championship was retired, making the Hart Dynasty the final champions. On the same night, Bret Hart presented The Hart Dynasty with brand new WWE Tag Team Championship belts. At Night of Champions, The Hart Dynasty lost the WWE Tag Team Championship to Cody Rhodes and Drew McIntyre in a Tag Team Turmoil match which also involved The Usos, Vladimir Kozlov and Santino Marella, and the team of Evan Bourne and Mark Henry. After a failed attempt to regain the championship, in which Kidd was pushed off balance during their double-team Hart Attack move, Kidd and Smith began to have a falling out with one another.
This culminated on the November 15 episode of Raw, when Kidd refused to tag in and attacked Smith during a match for the WWE Tag Team Championship against The Nexus (Justin Gabriel and Heath Slater). Kidd became a heel once again as a result of this. Smith defeated Kidd in a singles match on the November 25 episode of WWE Superstars. Afterward, Smith offered to shake Kidd's hand, but Kidd refused and instead slapped him across the face. On the following episode of Raw, Kidd defeated Smith in a rematch.
David Hart Smith was released from his WWE Contract on August 5, 2011.