The Hart Foundation were a legendary tag team comprised of Bret "Hit Man" Hart & Jim "The Anvil" Neidhart with Jimmy Hart as their manager, which competed exclusively in the World Wrestling Federation from 1985 until 1991. Additionally, The Hart Foundation were a faction in 1997 comprised of Bret Hart, Davey Boy Smith, Owen Hart, Jim Neidhart, and Brian Pillman. Unlike almost every other tag team in the history of wrestling, Bret & Neidhart never got into any serious arguments while working together or since then, according to Bret.
The Hart Foundation became the quintessential team of mixed partners where one man brought strength & power (Neidhart) and the other man brought finesse & agility (Bret). They won the WWF Tag Team titles in January 1987 from the British Bulldogs after the Dynamite Kid sustained an injury and he could not compete at 100% in the ring. Although the Bulldogs were sitting ducks, Jimmy Hart ensured his team's victory by bribing referee Danny Davis. The result saw a six-man tag match between the Harts & Davis against the Bulldogs & Tito Santana at WrestleMania III, which the Harts won.
Tito Santana & Rick Martel unseated the Hart Foundation in October 1987, just when Bret felt the Hart Foundation were truly gaining momentum, and the Hart Foundation continued as a team for the next several months. While Bret & Neidhart remained united, the Harts and Jimmy Hart did not. They fired him as their manager, but he still had active contracts for 25% of their pay, so he taunted them by claiming that he would share his earnings with the Fabulous Rougeau Brothers. This led to an obligatory feud between the Harts and Rougeaus. Additionally, the Hart faced two more of Jimmy Hart's charges at WrestleMania V when they beat Honky Tonk Man & Greg Valentine.
The Hart Foundation maintained their momentum together and before WrestleMania VI, they issued a "gauntlet" to the winner of the WWF Tag Team championship match between the Colossal Connection and Demolition, which Demolition won. The two teams met at SummerSlam '90 in a Best of Three Falls match and the Harts regained the WWF Tag Team titles with an assist from the Legion of Doom. The Harts reigned as champions until WrestleMania VII (minus a week-long controversy with The Rockers) where they lost the titles to the Nasty Boys (who were managed by none other than Jimmy Hart).
Bret Hart went into singles competition and Jim Neidhart repackaged the Foundation, creating the New Foundation and recruiting Bret's younger brother Owen as his partner. Neidhart left the WWF later in 1991 and the New Foundation became High Energy with Koko B. Ware replacing Neidhart.
In 1994, Bret and Owen became bitter rivals but Bret made amends with him after WrestleMania 13 and they formed the anti-American faction known as The Hart Foundation, which were reviled as villians in the USA but praised as heroes everywhere else. Bret led the Hart Foundation until the Montreal Screwjob and Bret, Neidhart, and Bulldog fled to WCW while Owen was forced to stay in the WWF (Pillman passed away six weeks prior to the split).