When Steele was brought in to the WWWF, he wrestled Bruno Sammartino to an hour-long draw at Madison Square Garden, but lost the rematch. In Boston, being set up to face Sammartino for a long series in that city, he got one of the few clean wins over Victor Rivera, a top babyface, with the flying hammerlock submission, at a huge Fenway Park outdoor show. He was then relegated to a feud with Chief Jay Strongbow, and lost to Edouard Carpentier at the Garden before taking a brief hiatus to reinvent his wildman character.
Steele became a true crazy heel, acting like a wild man in the ring, tearing up the turnbuckle with his teeth and using the stuffing as a weapon as well as sticking out his green tongue. "The Animal" had a stooped posture and a hairless head, but a thick mat of fur on his back; wrestling broadcasters often speculated that The Animal was indeed "the missing link". At best, The Animal could occasionally manage to utter a word or two during interviews with one of them usually being "Duh-da-dahh" or "YOU! YOU go!"
Steele eventually became one of the more popular and recognizable wrestlers during most of the 1980's. He turned face during Saturday Night's Main Event I when his partners in a six-man match, Nikolai Volkoff and The Iron Sheik, abandoned him to their opponents, Ricky Steamboat and the U.S. Express (Barry Windham and Mike Rotunda), leading to Steele being taken under the wing of the Express' manager, Captain Lou Albano, who consoled him following the loss. His most famous feud was in 1986 against "Macho Man" Randy Savage, after Steele developed a crush on Savage's valet, Miss Elizabeth. The feud was meant to last only a couple of months (and end with Steele being disappointed), but it proved so popular with fans that it continued well into 1987. During Savage’s Intercontinental Championship match against Steamboat at WrestleMania III, Steele—who was in Steamboat’s corner—twice interfered in the match. First, he took the ring bell from Savage as he attempted to use it off of the top rope. Secondly, after Savage kicked him and took the bell back, Steele shoved Savage off of the top rope, allowing Steamboat to roll up Savage for the pin to win the championship.
In 1988, Steele began carrying a stuffed animal named "Mine" to the ring. He participated in the WrestleMania IV Battle Royal but was outside of the ring the whole time. According to Steele, he suffered a knee injury at a house show prior to the event, which was the reason he didn't get in the ring. Late in 1988, Steele retired. Steele then became a road agent for the WWF until he was released in October 1990 due to budget cuts. Soon after, however, Steele was re-hired by the WWF and continued to work as an agent until the late 1990s. Though he left the WWF without any WWF championships behind him, Steele grew to become one of the most recognized and popular figures in WWF history and was inducted into the WWF Hall of Fame class of 1995.
In 1998, during the WWF's "Attitude Era", Steele briefly returned as part of The Oddities.
On January 10, 2000, he appeared on an episode of WCW Monday Nitro as one of three legends Jeff Jarrett had to face that night.
Steele made a surprise appearance on Monday Night Raw on November 15, 2010, during a match between Kofi Kingston and David Otunga.
Steele passed away on February 16, 2017.