From 1969 through 1973, Valiant enjoyed a protracted stint in the WWWF as "John L. Sullivan," a mid-card babyface, losing to top-tier heels like Killer Kowalski and Toru Tanaka, but repeatedly holding the notorious Baron Mikel Scicluna to a draw, and regularly defeating low-carders like Angelo Savoldi and Johnny Rodz.
After he retired from active competition, Valiant went on to have a successful career as a manager. He briefly managed Hulk Hogan until Hogan soon turned face in the AWA in the early 1980's. Valiant soon moved back to the WWF to manage Brutus Beefcake. The pair appeared at the inaugural WrestleMania event with Beefcake battling David Sammartino (seconded by his father Bruno Sammartino) to a double disqualification after Valiant slammed David on the floor before being attacked by Bruno who threw him into the ring where all four continued the fight. Valiant and Beefcake were also regulars on other WWF television shows including the weekly syndicated WWF Championship Wrestling.
Soon after in May 1985, Valiant and fellow heel manager Jimmy Hart put together The Dream Team with Beefcake teaming with then Intercontinental Champion Greg Valentine. After initially feuding with Tito Santana (who reclaimed the Intercontinental Title from Valentine in July) and the Junkyard Dog, The Dream Team began to challenge The U.S. Express (Barry Windham and Mike Rotundo) for the WWF World Tag Team Championship after Valentine had lost the Intercontinental Title to Santana in July. On August 24, 1985 at The Spectrum in Philadelphia, Valiant led the Dream Team to the Tag Team Championship, when they defeated The U.S. Express after Beefcake rubbed Johnny V's lit cigar in Windham's eyes. The Dream Team held on to the title for eight months, facing challenges from teams such as the U.S. Express and The Killer Bees (Jim Brunzell and B. Brian Blair) before losing it to the British Bulldogs (Dynamite Kid and Davey Boy Smith) in the Chicago segment of WrestleMania 2. The Dream Team chased the Bulldogs for the next few months but were unsuccessful in regaining the championship belts.
Johnny V added Dino Bravo to his stable in early 1987. At WrestleMania III in front of 93,173 at the Pontiac Silverdome, Valiant, Valentine and Bravo abandoned Beefcake in the ring after the Dream Team had defeated The Rougeau Brothers (Jacques and Raymond) and The New Dream Team of Valentine and Bravo was born. Not as successful as the first incarnation, this Dream Team had a lengthy feud with the scorned Beefcake, now nicknamed "The Barber", who cut Johnny V's hair on an episode of Superstars of Wrestling when an overly confident Valiant had given the New Dream Team the night off. The New Dream Team initially feuded with The Islanders (Haku and Tama) as well as continuing the feud with the Rougeaus. The Dream Team also had a couple of unsuccessful Tag Team Championship matches against then-champions The Hart Foundation (Bret Hart and Jim Neidhart). These matches were unusual for the time as both teams were heels with The Hart Foundation managed by Jimmy Hart.
Also in this stint in the WWF, Johnny V was known to do commentary on matches from time to time (filling in on Wrestling Challenge for fellow heel manager/commentator Bobby "The Brain" Heenan when he had to leave the broadcast booth to manage one of his wrestlers) and introduced the team of Demolition (Ax and Smash). After a few months, Demolition was managed by Mr. Fuji.
One of Valiant's last appearances as a manager in the WWF was at the 1987 Survivor Series. After this show, Valiant was phased out as manager of the New Dream Team and was then relegated to the role of a wrestler once again, as a jobber to the stars. Valiant left the WWF in March 1988, just before WrestleMania IV, and then returned to the AWA as a manager and led the Destruction Crew (Wayne Bloom and Mike Enos) to the AWA World Tag Team Championship in 1989 (defeating Greg Gagne and Paul Diamond in a tournament final).
In 1996, Valiant was inducted into the WWF Hall of Fame alongside long-time tag partner Jimmy Valiant.
On April 4, 2018, Valiant passed away.