Valentine began working on a casual basis for the World Wide Wrestling Federation (WWWF), then owned by Vincent J. McMahon, in November 1978.

Managed by The Grand Wizard, he was given the gimmick of a methodical wrestler who broke the legs of all his opponents, including Chief Jay Strongbow.

In February 1979, he wrestled then WWWF Heavyweight Champion Bob Backlund to a one-hour time-limit draw at Madison Square Garden.

Four days after their victory, the promoter, David Crockett told Valentine and Stevens that he possessed film which proved that the illegal man had been pinned in the tag match, nullifying the win.

[6] He also feuded with Pedro Morales over the WWF Intercontinental Heavyweight Championship, who he "injured" by suplexing him on the concrete floor of the arena.

Valentine would hold the United States Championship twice more, renewing his feud with Wahoo in 1982 and defeating him for the title on November 4 with the assistance of his manager, Sir Oliver Humperdink.

The feud was intensified by Valentine's propensity to focus on Piper's ear, which had been injured earlier in his career and would bleed easily.

While Santana was sidelined having leg surgery, Valentine feuded with the Junkyard Dog, who he faced in an Intercontinental Heavyweight Championship Title match at the very first WrestleMania held in Madison Square Garden.

They held the titles until April 7, 1986, when they were defeated at WrestleMania 2 by The British Bulldogs (Davey Boy Smith and the Dynamite Kid).

At WrestleMania III, The Dream Team defeated the Rougeau Brothers as a result of interference by Johnny V and Dino Bravo.

The feud was triggered when Valentine viciously attacked Muraco's manager, former WWF Heavyweight Champion Superstar Billy Graham.

Graham, walking with a cane, tried to intervene when Valentine held the figure-four leglock on jobber Ricky Ataki, after already winning the match.

[7] (Kayfabe magazine Inside Wrestling had run a story on the feud, conversely claiming that it was Muraco, yearning to personally avenge Graham's injuries, who had begged the WWF not to dismiss Valentine).

An angle was recorded on December 28, 1990, at Madison Square Garden where he was defeated by Saba Simba after accidentally being hit by Jimmy Hart's guitar; afterwards he almost attacked his manager and began to be cheered by the fans.

In a match that saw Davey Boy Smith defeat Dino Bravo, Valentine was again accidentally hit by Jimmy Hart's megaphone.

On the February 17, 1991 edition of Wrestling Challenge, the WWF aired footage from the incident with Jimmy Hart at Madison Square Garden at the end of 1990.

Valentine lost to the Jimmy Hart managed Earthquake at WrestleMania VII, and was defeated again at SummerSlam 1991 by Irwin R. Schyster.

He participated in the 1992 Royal Rumble for the vacated WWF Championship, where he attacked his old rival Ric Flair before being eliminated by the Repo Man.

[11] Herb Abrams had aggressive plans for his Universal Wrestling Federation, announcing the signings of name wrestlers such as Andre the Giant, Steve Williams, The Killer Bees, and Bob Orton.

He made his debut that night at a television taping in the Penta Hotel in New York City, defeating Sonny Blaze.

[12] He later defeated Mike Durham at the same taping, and was interviewed by Albano, his former WWF manager in the "Captain Lou's Corner" segment on UWF television.

However his stay in the UWF was technically only for that TV taping; as with Andre the Giant, Vince McMahon responded to Abram's announcement by luring Greg Valentine back to the WWF.

That summer Valentine would wrestle three times on a July house show tour, facing Bob Backlund on each occasion.

[17] On October 10, 1999, he appeared on the infamous Heroes of Wrestling pay-per-view, pinning George "The Animal" Steele with the assistance of Sherri Martel.

On October 3, 2005, Valentine made an appearance at WWE Homecoming, and on October 23 he was defeated by Rob Conway (then using a gimmick similar to that of Randy Orton's gimmick of "the legend killer") on an episode of WWE Heat after Eugene interfered on his behalf, causing the referee to award a victory via disqualification to Conway.

In late 2007, Valentine made an appearance in JCW or Juggalo Championship Wrestling reforming the Dream Team with Brutus Beefcake.

Valentine was present at the retirement ceremony of his long-time friend, Ric Flair, on the March 31, 2008 episode of WWE Raw.

On January 29, 2011, Valentine was inducted into the Legends Pro Wrestling "Hall of Fame" by Jack Blaze in Wheeling, West Virginia, at their annual "LPW Over The Edge" event.

He had two daughters, Vanessa and Romaine, with his first wife, who once appeared on WWF TV in 1984 to give Valentine a back rub, which he claimed was the secret of his success.

In 2008 Valentine co-starred with George "The Animal" Steele in a short film entitled Somethin Fishy, in which the two former wrestlers purchase a fishing camp.