Rex joined the World Wrestling Federation in 1980, debuting under the name Ripper Hawkins. Within a few weeks, he was re-packaged as Moondog Hawkins, soon after that being renamed Moondog Rex. Eventually, he was teamed with Moondog King as The Moondogs tag team. In 1981 he won the WWF Tag Team Championship with Moondog King (later replaced by Moondog Spot). On August 21, 1981, the Moondogs would lose the Tag Team Championship to Rick Martel and Tony Garea. On September 1, 1981, he mounted an unsuccessful challenge to WWF World Heavyweight Champion Bob Backlund, but was defeated.
The Moondogs made their return to the WWF on the March 4, 1984 edition of All American Wrestling and defeated Bobby Fulton and Brian Madden. The new duo remained undefeated until June 30, where they lost a Los Angeles house show match to The Wild Samoans. The Moondogs continued to unsuccessfully feud with the Samoans throughout that summer. In June 1984, Rex received two singles shots against WWF Champion Hulk Hogan on the Canadian television tapings that aired on both Maple Leaf and All-Star Wrestling. In September 1984, they were programmed into a house show series against the newly arrived Fabulous Freebirds. While continuing to defeat preliminary opposition on television, the Dogs were winless against the Freebirds. Following departure of Michael Hayes, Terry Gordy, and Buddy Roberts from the promotion, the Moondogs feuded with the Brisco Brothers.
The Moondogs entered 1985 on the lower end of the tag team ranks, and were split apart as singles wrestlers to help flesh out house show cards. Rex lost singles matches to Bret Hart, Barry Windham, Jimmy Snuka, Jerry Brisco, and Tony Atlas to start the year, before going on a winning streak that saw him defeat Bobby Colt and Rick McGraw on the house show circuit. This would continue until April 1985, at which point Rex left the WWF.
On February 22, 1986, Rex made his return to the WWF on a house show in Melbourne, Australia and lost to Jacques Rougeau. On April 14, he was reunited with Moondog Spot, losing to The Rougeau Brothers on Prime Time Wrestling. Rex now found himself in a similar position as in his previous WWF run, defeating preliminary opposition but losing to more established teams. The Moondogs were programmed into a feud with Tony Atlas and Pedro Morales and would also face The U.S. Express as they entered the summer of 1986. Their most high profile match came on the July 12, 1986 edition of WWF Championship Wrestling, where they lost to WWF World Champion Hulk Hogan and Paul Orndorff; the match being worked entirely by Orndorff and part of the famous feud between the latter that would begin shortly. In the fall of 1986, they began a house show series with The Islanders and finished the year facing The Killer Bees and U.S. Express.
On January 4, 1987, in Springfield, Massachusetts, Rex was repackaged as Smash in the new tag team of Demolition, facing and defeating the Islanders The following day in East Rutherford, New Jersey, he made his televised debut at a WWF Superstars taping. Despite having his hair trimmed, his beard shaved off, and wearing face paint, fans almost immediately recognized him and began chanting "Moondog" when he entered the ring. Following a third appearance, this time at a Wrestling Challenge taping, he was replaced by Barry Darsow.
Rex was soon repackaged again as part of the masked wrestling team The Shadows with partner Jose Luis Rivera. They made their debut under their new gimmick on April 23, 1987 in Worcester, Massachusetts at a WWF Superstars taping, defeating Lanny Poffo and Nick Kiniski in a dark match. Their first television appearance would come on the May 16 edition of Superstars, where they teamed with Iron Mike Sharpe and were defeated by Billy Jack Haynes, Tito Santana, and Blackjack Mulligan. Unlike Demolition, The Shadows were used as enhancement talent and embarked on a lengthy losing streak to The Young Stallions on the house show circuit that spring. It would be several months later before the new team would gain their second victory, as it was July 24, 1987 when they finally had their hands raised when they defeated Lanny Poffo and SD Jones at a house show in Detroit, Michigan. However, that would be Rex's final victory in the promotion as the Shadows dropped matches to The Killer Bees, Rougeau Brothers, and Strike Force during the summer and fall of 1987. The duo disbanded after Rex left the company at the end of October 1987.
He would return in a one-off on November 26, 1988. Wrestling simply as The Shadow, he was defeated by Boris Zhukov at a house show in Detroit, Michigan.
In the summer of 1990, Rex debuted in WCW as Moondog Rex in singles competition. His first match was at a July 6 house show in Norfolk, Virginia, against El Gigante. His televised debut came several months later, when he appeared on World Championship Wrestling on September 29, and defeated Reno Riggins. Rex's highest profile match was losing to the Junkyard Dog at Halloween Havoc. He continued to appear on televised programs and house shows into the spring of 1991.
In May 1991, World Championship Wrestling created a stable known as "the Desperados" consisting of Dutch Mantell, Black Bart, and Rex, who played Deadeye Dick. The Desperados were packaged with the gimmick of being three bumbling cowboys looking to meet Stan Hansen to go to WCW and become a team. Over the course of a few weeks, they were promoted through a series of vignettes in which they were beaten up in saloons, searched ghost towns, were jailed, and rode horses. The Desperadoes entered the ring for the first time at house show in Charlotte, North Carolina on May 12, 1991, where they (Bart and Dutch Mantell) were defeated by The Young Pistols.
Later that month, Deadeye began teaming regularly with Black Bart in house show matches against Ricky Morton and Dustin Rhodes. The full Desperadoes trio entered the ring for the first time on July 3, 1991 in East Rutherford, New Jersey at the start of the 1991 The Great American Bash tour, where they were defeated by The Freebirds and Badstreet Brad Armstrong.
While the Desperadoes angle continued and the trio was shown as late as the June 29 WCW Power Hour program still looking for Stan Hansen, Hansen left WCW. Without Hansen, the group were dissolved as a stable, with Deadeye finishing his run following a loss to the Freebirds on July 21, 1991 in Knoxville, Tennessee.
On December 14, 2019, Rex passed away.