Saito competed in freestyle wrestling for Japan in the 1964 Summer Olympics, placing seventh.
Saito began his pro wrestling career in 1965 and quickly established himself in both Japan and the United States. Nicknamed "Mr. Torture" for his punishing and sadistic style, Saito held numerous titles while wrestling in North America and Japan.
On July 13, 1968, Saito won his first title, teaming with Kenji Shibuya to win the San Francisco version of the World Tag Team Championship. The following year, he defeated Dale Lewis to win the NWA Florida Heavyweight Championship. After losing the title to Jack Brisco on February 10, 1970, he continued to team with Shibuya in the Los Angeles-based NWA Hollywood Wrestling, winning the NWA Americas Tag Team Championship three times in 1971 and 1972. While wrestling in Los Angeles, he also won the NWA Beat the Champ Television Championship twice in 1972.
Saito's next championship came in Vancouver, British Columbia, where he teamed with Gene Kiniski to win the Vancouver version of the Canadian Tag Team Championship. They held the belts for almost four months before dropping them to Ormand Malumba and Guy Mitchell on March 3, 1975. Saito regained the championship later in the year, however, teaming with Dale Lewis.
Saito next wrestled in NWA Florida, where he teamed with Ivan Koloff to defeat Rocky Johnson and Pedro Morales for the NWA Florida Tag Team Championship in 1977. After losing the belts, Saito and Koloff won them twice more. Their final loss, on January 25, 1978 was to Jack and Jerry Brisco. Saito regained the title, however, teaming with Mr. Sato to defeat the Brisco Brothers. They lost the belts back to the Brisco Brothers three months later but succeeded in regaining them from Mike Graham and Steve Keirn later in the year. While wrestling in Florida, Saito also teamed with Sato to win the NWA Florida United States Tag Team Championship on two occasions in 1978 and 1979. In 1979, he also won the Japan version of the North American Tag Team Championship, teaming with Hiro Matsuda to win the belts on April 5.
Wrestling in the United States again in 1981, Saito won the Alabama Heavyweight Championship twice, defeating Bob Armstrong and Ray Candy. That year, he was also involved in a controversy regarding the Florida version of the North American Tag Team Championship. The Assassins were stripped of the title when it was discovered that Saito was wrestling under a mask as a third member of the team.
Later in the year, Saito signed with the World Wrestling Federation. He formed a tag team with Mr. Fuji, which was managed by Captain Lou Albano. They began a feud with tag champions Tony Garea and Rick Martel, whom they defeated on edition of October 17, 1981 of Championship Wrestling to win their first WWF Tag Team Championship, though it was Fuji's fourth individual reign. They began feuding with The Strongbows (Chief Jay and Jules) in the fall of 1981. This culminated in a title match on June 28, 1982 at Madison Square Garden (MSG) where Strongbows won the titles. On edition of July 13 of Championship Wrestling, they defeated Strongbows in a two out of three falls match for Fuji's fifth and Saito's second WWF Tag Team Championship. The feud of these two teams ended after Fuji and Saito lost the titles to Strongbows on edition of October 30 of Championship Wrestling.
Saito spent the bulk of 1982 and 1983 with the American Wrestling Alliance.
According to police, on April 6, 1984, Ken Patera was refused service at a McDonald's restaurant after the restaurant had closed, and threw a boulder through the restaurant's window in retaliation. The responding officers testified that later, when they arrived at Saito and Patera's hotel room to investigate someone matching Patera's description in connection with the criminal damage report, Saito was uncooperative and both wrestlers assaulted the officers, taking turns beating them until other officers arrived to subdue them. As a result of the incident, Saito and Patera were convicted of battery of a police officer and sentenced to serve two years in prison.
On November 16, 2012, Patera was interviewed on KFAN radio based out of Minneapolis, MN. In describing the incident, he stated that he went to the McDonald's around midnight to get a burger, but found it closed. The lights were on because they were shooting a commercial, so not only Patera but another customer (who he described as a young adult) had arrived, thinking that they were open for business. The young adult threw a rock through the window, but Patera was blamed. Saito was never there.
Following his release, Saito wrestled mainly in Japan, where he became involved in a feud with Antonio Inoki. To settle the feud, the two competed in an Island Death match on October 4, 1987. They were placed on Ganryujima Island and wrestled a match that lasted two hours and spread across the island. Ultimately, Inoki was victorious, defeating Saito by technical knockout. The following year, after leaving All Japan Pro Wrestling to return to New Japan Pro Wrestling, Saito won his first IWGP Tag Team Championship while teaming with Riki Choshu. He followed this with a second victory the following year, this time with Shinya Hashimoto.
Saito's final major title came in the American Wrestling Association (AWA), where he defeated Larry Zbyszko for the AWA World Heavyweight Championship in front of a hometown crowd of 63,900 fans at the Tokyo Dome on February 10, 1990. He lost the title two months later in a rematch with Zbyszko at SuperClash 4. While wrestling in the AWA about a decade earlier, Saito formed a tag team with Jesse Ventura known as the Far East-West Connection.
Saito had a couple short stints in World Championship Wrestling (WCW). His first came in 1990, which saw him team with The Great Muta for the Pat O'Connor Memorial Tag Team Tournament at Starrcade '90: Collision Course, which they lost to The Steiner Brothers in the finals. It wouldn't be until five years later that Saito briefly returned, which included an appearance at Starrcade '95. Wrestling as part of a series of matches between New Japan Pro Wrestling and World Championship Wrestling, Saito lost his match to WCW representative Johnny B. Badd by disqualification.
On February 14, 1999, Saito retired from wrestling. His last match was a loss to Scott Norton. Starting in 2006, Saito worked with the Diamond Ring promotion as a supervisor and manager/advisor to the promotion's younger talent. Diamond Ring ran its last show in February 2014.
In 2000, Saito was diagnosed with Parkinson's disease.Finishing moves
Saito suplex – Innovated
Prison Lock (Kneeling figure four leglock)
American Wrestling Association
AWA World Heavyweight Championship (1 time)
Championship Wrestling from Florida
NWA Florida Heavyweight Championship (2 times)
NWA Florida Tag Team Championship (5 times) – with Ivan Koloff (3) and Mr. Sato (2)
NWA United States Tag Team Championship (Florida version) (2 times) – with Mr. Sato
New Japan Pro Wrestling
IWGP Tag Team Championship (2 times) – with Riki Choshu (1) and Shinya Hashimoto (1)
NWA North American Tag Team Championship (Los Angeles/Japan version) (1 time) – with Hiro Matsuda
NWA All-Star Wrestling
NWA Canadian Tag Team Championship (Vancouver version) (2 times) – with Gene Kiniski (1) and Dale Lewis (1)
NWA Hollywood Wrestling
NWA Americas Tag Team Championship (3 times) – with Kenji Shibuya
NWA "Beat the Champ" Television Championship (2 times)
NWA San Francisco
NWA World Tag Team Championship (San Francisco version) (2 times) – with Kenji Shibuya
Pro Wrestling Illustrated
PWI ranked him #89 of the top 500 singles wrestlers of the "PWI Years" in 2003
Southeastern Championship Wrestling
NWA Alabama Heavyweight Championship (2 times)
World Wrestling Federation
WWF World Tag Team Championship (2 times) – with Mr. Fuji
Wrestling Observer Newsletter
Best Technical Wrestler (1984)