
In 1970, he began wrestling in Vince McMahon, Sr.'s World Wide Wrestling Federation (WWWF). Wrestling as Bepo Mongol, managed by "Captain" Lou Albano and partnered with Geto Mongol as The Mongols, he captured the WWF International Tag Team Championship from Tony Marino and Victor Rivera on June 15, 1970. After losing the title to Luke Graham and Tarzan Tyler in a match over a year later that unified the WWWF International and WWWF World Tag Team Championship, Volkoff left the WWWF.
In 1974, Volkoff returned to the company and appeared in a memorable match at a sold out Madison Square Garden against Bruno Sammartino. In 1976, he was masked as an Executioner as he became the third member along with Killer Kowalski and Big John Studd. They captured the World Tag Team Championship, but it was vacated due to a third member interfering. Later, he reverted to the Volkoff name. During this time in the WWWF, Volkoff was announced as being from Mongolia. He had a very successful feud with Bruno Sammartino, which started when Volkoff attacked him during an interview segment. They sold-out arenas throughout the Northeast. During this tenure, he began crushing fresh apples with one hand as a sign of what he would do to his opponents. He later had a feud with Bob Backlund during Backlund's tenure as champion.
Late in 1974, Volkoff moved to the AWA where he wrestled under the name Boris Breznikoff, managed by Bobby "The Brain" Heenan.
In July 1984, Volkoff returned to the renamed WWF defeating SD Jones and teaming with the Iron Sheik, with the pair being managed by "Classy" Freddie Blassie. It was at this point that Volkoff began to sing the national anthem of the Soviet Union before every match after which the Sheik would grab the microphone and proclaim "Iran number one, Russia number one" before exaggeratedly spitting after saying "USA", in order to gain even more heat for being foreign heels.
The new team of Volkoff and the Iron Sheik captured the WWF Tag Team Championship from The U.S. Express (Mike Rotundo and Barry Windham) at the first WrestleMania, on March 31, 1985, after the Sheik had knocked out Windham with Fred Blassie's cane. After losing the title back to Rotundo and Windham three months later, Volkoff began to wrestle more in singles competition. He faced Hulk Hogan for the WWF World Heavyweight Championship on several occasions in 1985 and 1986 (including a flag match on Saturday Night's Main Event II).
Volkoff also feuded with Corporal Kirchner throughout 1985 and 1986, defeating him in a "peace match" on Saturday Night's Main Event IV. Their feud ended when Kirchner used Blassie's cane to defeat Volkoff at WrestleMania 2 in another flag match during the Chicago portion of the event.
In the fall of 1986, Volkoff's manager "Classy" Freddy Blassie sold half interest in his stable of superstars to the "Doctor of Style" Slick, giving Slick co-managerial rights to Volkoff. Blassie also shared the contracts of the Iron Sheik and Hercules. Sheik and Volkoff feuded with WWF newcomer Jim Duggan for the majority of 1987, including Duggan running to the ring and stopping the Russian's singing before their match against The Killer Bees at WrestleMania III (Sheik and Volkoff won by disqualification when Duggan entered the ring while chasing Volkoff and then hitting the Sheik with his 2x4 while he had the camel clutch on "Jumping" Jim Brunzell).
In late 1987, Volkoff was teamed with Boris Zhukov, another alleged Russian, to form The Bolsheviks. They feuded with WWF newcomers The Powers of Pain, losing to them at the inaugural SummerSlam pay-per-view in 1988, however The Bolsheviks did not gain the success as did his partnership with The Iron Sheik. As they lost the public eye due to many losses, they eventually lost their manager Slick and were used as a comic relief team losing many matches to The Bushwhackers. The Bolsheviks never held any titles together, and are perhaps best remembered for being defeated in 19 seconds by The Hart Foundation at WrestleMania VI.
On October 29, 1989 he returned to AWA for a one night appearance, as he lost to Ken Patera.
Eventually, by 1990, The Bolsheviks split up. Volkoff publicly ended the partnership prior to a match where he confronted Zhukhov and then started singing "The Star-Spangled Banner", drawing loud cheers from the audience and turning babyface in the process.
A short time after The Bolsheviks split, Volkoff became a face for the first time in his career. His gimmick was now that of a recent defector, he became very pro-west which led to a feud with Sgt. Slaughter who had an Iraqi sympathizer role and teamed with the former Iron Sheik, who had recently begun an Iraqi gimmick under the name Colonel Mustafa. After Volkoff's team defeated Slaughter's team at the 1990 Survivor Series (Tito Santana was the sole survivor), Volkoff left the WWF at the end of 1990.
He made a brief return to compete in the 1992 Royal Rumble match, as well as to face Hercules in a house show match on January 29 in Lowell, Massachusetts.
In 1992, he went to Extreme Championship Wrestling, where he feuded with Vladimir Markoff. On October 2, he lost to ECW Champion Don Muraco.
He returned as a babyface to pin Barry Horowitz at a WWF Superstars/All-American Wrestling taping on July 6, 1993, in Wilkes-Barre, Pennsylvania.
He then returned to ECW on October 16, 1993 as he lost to Jimmy Snuka.
On February 1, 1994, Volkoff began a full-time return to the WWF, making a ringside appearance at a Superstars taping in White Plains, New York during a match between Diesel and Mike Moraldo. For the next two months, Volkoff was shown in the crowd, until eventually he became a sympathetic heel by playing the whipping-boy of Ted DiBiase's Million Dollar Corporation. Volkoff had kayfabe fallen on hard times and was forced to take a job working for DiBiase and his new Corporation. As low man in the group he was forced to wrestle matches no one else wanted to or sent out to "soften up" opponents for other members of the stable as the sacrificial lamb of the group. The disrespect even extended to renaming him "Nickel & Dime" Volkoff and DiBiase forcing him to place a ¢ on his trunks where the Russian sickle once was along with a sign on his ring attire that read "Property of The Million Dollar Man". The final WWF match for Volkoff was on December 30, 1994 when he defeated jobber Bob Starr in a house show. Volkoff's final appearance was at the WWF's final show at The Boston Garden on May 13, 1995. During a match between WWF Champion Diesel and Sid, Volkoff made an appearance to chase Sid's manager Ted DiBiase away.
Volkoff made a brief cameo on an episode of Shotgun Saturday Night in 1997, where Todd Pettengill discovered him homeless sleeping in a box on the streets of New York City. He also appeared at WrestleMania X-Seven at the Astrodome in Houston in the gimmick battle royal which was won by The Iron Sheik.
On February 3, 2005, Volkoff was announced as one of the WWE Hall of Fame inductees for the class of 2005. He was inducted on April 2, 2005 by Jim Ross.
Volkoff made his first appearance on WWE television in over two years on the August 13, 2007 episode of Raw as a contestant on WWE Idol. Volkoff appeared alongside the Iron Sheik and Howard Finkel, although Volkoff was the only one who sang. Volkoff sang the Soviet Union national anthem, receiving boos from the crowd (despite being a babyface) and was insulted by judge William Regal, although judges Mick Foley and Maria both praised the performance. In response, Sheik, who was also insulted, went on a tirade until both he and Volkoff were escorted out of the building by security.
On the March 10, 2008 edition of WWE Raw, the Iron Sheik appeared along with Nikolai Volkoff to face off against the U.S. Express in a rematch from the first WrestleMania. However, the match never got started as Jillian Hall came out to interrupt Volkoff's singing.
On the November 15, 2010, edition of Raw, as part of the "old school" theme, Volkoff appeared with the Iron Sheik, singing the Soviet national anthem before being interrupted by Santino Marella and Vladimir Kozlov, the latter of whom then sung a duet with Volkoff of the Soviet national anthem.
On the January 6, 2014 "Old School" episode of Raw, Volkoff encountered Big E Langston on his way to a match and sung him the Soviet national anthem, to which Langston smiled. Immediately after, Langston walked past fellow Million Dollar Corporation members, Ted DiBiase and Irwin R. Schyster.
On the Raw Fallout segment following the September 8, 2014 Raw, Volkoff appeared backstage with Rusev and Lana and sang the Soviet national anthem.
On July 29, 2018, Volkoff passed away.