As Hart was accepting induction for the second time — this time as part of the tag team The Hart Foundation, along with the late Jim "The Anvil" Neidhart — Zachary Madsen rushed into the ring and hit him.
Madsen, of Lincoln, Nebraska, was charged with assault and criminal trespassing and held on a $1,500 bond in Brooklyn criminal court, where he explained his simple motivation.
The live broadcast on the WWE Network was interrupted as several people, including many wrestlers, rushed in the ring to pull Madsen away from Hart, who was alongside Neidhart's daughter, Natalya. Natalya, who is a WWE wrestler herself, was also slung to the ground during the skirmish.
A WWE security guard, Thaddeus Jones, was injured in the attack, and the Brooklyn judge issued protection orders barring Madsen from going near the guard or Hart.
"An over-exuberant fan surpassed our security at ringside and made his way briefly into the ring," WWE later said in a statement obtained by ESPN. "The individual has been turned over to the proper authorities."
Natalya, whose real name is Natalie Neidhart, responded to the attack after the ceremony, saying her uncle "didn't deserve to be attacked or have his moment or my dad's diminished." Jim Neidhart died suddenly last August.
Security and a host of wrestlers, including Hart's nephew Davey Boy Smith Jr., held down Madsen until police arrived and took him into custody. Smith tweeted the man was "lucky I was being held back."
Madsen was taken to the 78th Precinct, just blocks from Barclays Center. He has a prior arrest in Lincoln, Nebraska for stalking mixed martial artist Haris Talundzic in September.
Hart was able to finish his speech.
Wrestlemania, WWE's biggest event of the year, will take place at MetLife Stadium in New Jersey on Sunday night.
ABC News' Alexandra Svokos contributed to this report.