In 1963, Vincent J. McMahon hired Monsoon to the WWWF and he became one of the promotion's top heels, feuding with popular babyface champion Bruno Sammartino in sellout arenas across the country. Despite his huge size, then in excess of 400 pounds, Monsoon had great agility and stamina, often wrestling Sammartino to one-hour time-limit draws.
Monsoon teamed up with Killer Kowalski with success. In November 1963, they defeated Skull Murphy and Brute Bernard to win the U.S. Tag Team Championship. The following month, the duo lost the belts to the Tolos Brothers (Chris and John) in Teaneck, New Jersey. Monsoon and Kowalski reunited in the late 1960s to defeat champion Bruno Sammartino and Victor Rivera two falls to one in Madison Square Garden in a main event, marking the first, and possibly only time, that Sammartino and Rivera lost as a tag team.
Monsoon also teamed with Professor Toru Tanaka, and they had a number of tag matches in Madison Square Garden. They won a main event on disqualification over Sammartino and Spiros Arion and later lost a Texas Death rematch to the same team. A year later, after defeating teams such as Al Costello and Dr. Bill Miller and Bobo Brazil and Earl Maynard, they went on to lose a main event to Sammartino and Victor Rivera. Monsoon had semi main event matches with Spiros Arion as well as Bobo Brazil in his key heel years.
In 1969, Monsoon became a babyface, befriending his former arch-rival when Sammartino rescued him from an attack by "Crazy" Luke Graham. The stage was set for Monsoon to become a fan favorite of the 1970s and feud with top heels of the decade, including champion Superstar Billy Graham. He turned heel for a short time in 1977 and feuded with André the Giant, and the two engaged in a special boxing match in Puerto Rico, with André winning the match.
As a face, he had major wins in Madison Square Garden, including over Killer Kowalski as well as "Big Cat" Ernie Ladd.
On June 2, 1976, a famous incident occurred in Philadelphia involving boxing great Muhammad Ali during a taping for the syndicated WWWF TV show. Ali, preparing for his upcoming crossover bout with Antonio Inoki in Japan later that month, jumped into the ring as Monsoon (who rarely appeared as a wrestler on their TV shows) was concluding a short match against Baron Mikel Scicluna. Ali removed his shirt and started dancing around Monsoon while gesturing and throwing jabs at him, to which Monsoon responded by grabbing Ali in his Airplane Spin and slamming him to the mat.
On June 16, 1980, a young and up-and-coming Hulk Hogan was booked to face him at Madison Square Garden. At the time, Hogan was a widely followed heel character, while Monsoon was still a babyface. However, in order to push the new talent, McMahon told Hulk Hogan to beat Monsoon in under a minute. Upon that outcome, the crowd became livid and chased Hogan when he was leaving the arena.
As the 1980's began, Monsoon's in-ring career wound down. On August 23, Monsoon put his career on the line in a match against Ken Patera. Monsoon lost the match and only wrestled a few more matches, retiring several weeks later. He stayed true to his word and returned just three times: wrestling a six-man tag team match at Madison Square Garden in 1981, a match in 1982 as a substitute for André the Giant, and taking part in Big John Studd's "Body Slam Challenge" in 1983. The next phase of his career began, as the voice and backstage manager of WWF.
Monsoon would then become an announcer for the WWF starting in 1982. In addition, Vince McMahon, Jr. needed a new commentary team to head up his television programming, and installed Monsoon with the recently retired Jesse "The Body" Ventura in 1985.
Monsoon and Ventura had great chemistry, with Ventura as the pro-heel color commentator and Monsoon as the pro-face "voice of reason". Gorilla and Ventura called five of the first six WrestleManias together (the notable exception was WrestleMania 2, where Monsoon commentated on the Chicago portion of the event with Gene Okerlund, Cathy Lee Crosby and Ernie "The Cat" Ladd while Ventura commentated on the Los Angeles portion with Lord Alfred Hayes and Elvira).
The Ventura/Monsoon duo of heel and babyface were the original broadcast duo, setting the standard which all who followed would attempt to emulate, especially Ventura's charismatic pro-heel character which was a first of its kind as previous wrestling commentators had almost always been in favor of the fan favorites. The pair commentated on all the WWF pay-per-views together with the exception of the first two SummerSlams and the 1990 Royal Rumble (at SummerSlam 1988, Ventura was the guest referee for the main event so Monsoon commentated with "Superstar" Billy Graham, while Ventura was paired with Tony Schiavone at both SummerSlam 1989 and the Royal Rumble). When Ventura left the WWF in mid-1990, he was replaced in commentary by Monsoon's Prime Time Wrestling co-host, heel manager Bobby "The Brain" Heenan. Other people who were often paired with Monsoon in the broadcast booth included Lord Alfred Hayes, Johnny Polo, "Superstar" Billy Graham, Hillbilly Jim, Tony Schiavone, Jim Neidhart, Randy Savage and Jim Ross.
Monsoon called the first eight WrestleManias from 1985 to 1992. Monsoon was the lead commentator on the syndicated show, WWF All Star Wrestling, its successor WWF Wrestling Challenge, and the USA Network weekend show, WWF All American Wrestling, as well as hosting the WWF weeknight show, Prime Time Wrestling.
Monsoon stepped down as the WWF's lead commentator at WrestleMania IX (where he was Master of Ceremonies) to make way for WCW recruit Jim Ross. He was phased out of Wrestling Challenge with Bobby Heenan and was moved to All-American Wrestling with Lord Alfred Hayes on April 11, 1993. He commentated with Jim Ross on WWF Radio for the broadcasts of SummerSlam 1993, Survivor Series 1993 and Royal Rumble 1994. He returned to the television broadcast team to call the King of the Ring 1994 with Randy Savage as well as covering a few episodes of Monday Night Raw in 1993 and 1994 whenever Vince McMahon was unavailable. He was also called upon sporadically to return to Challenge from 1993 to 1995, calling action with Stan Lane, Ted DiBiase, and Ross again. Monsoon also did various work for Coliseum Video. Monsoon's last pay-per-view commentary was for the 1994 Survivor Series, with Vince McMahon on play-by-play. Monsoon remained in his backstage role and appeared on-air frequently, becoming the storyline WWF President in the summer of 1995 (replacing Jack Tunney). The WWF President's role was to arbitrate disputes between wrestlers and make matches, similar to the current WWE general managers. It was during this time that, after he was attacked and (kayfabe) severely injured by Vader, that Roddy Piper became interim WWF President until WrestleMania XII, when Monsoon assumed the position again. Health concerns forced him to relinquish this role during the summer of 1997. Instead of naming a replacement, the WWF decided to retire the role of "President" and introduced Sgt. Slaughter as the new WWF Commissioner in August 1997. In late 1998, Monsoon returned briefly to call the international version of WWF Superstars. In 1999, Monsoon appeared in a WWF Attitude commercial featuring Freddie Blassie, Ernie Ladd, Pat Patterson and Killer Kowalski. His final appearance on WWF television before his death was as one of the three judges for a Brawl for All contest between Bart Gunn and Butterbean at WrestleMania XV. Because of his frail appearance and rapidly declining health, the camera only focused on Monsoon during his introduction as a judge, for which he received a standing ovation.
Monsoon passed away on October 6, 1999.
In a tribute that aired on October 11, 1999, on an episode of Raw Is War from the Georgia Dome, McMahon described Monsoon as "one of the greatest men I have ever known." WCW commentator Tony Schiavone acknowledged Monsoon's death on the October 11, 1999, episode of WCW Monday Nitro. Monsoon was inducted into the WWF Hall of Fame, class of 1994, on June 9.