His wrestling record at the senior level was 887 wins and two losses, both considered controversial and both by a single point.

[13][2][14][10][15] Prior to his defeat to American Rulon Gardner at the 2000 Olympics finals, a point had not been scored against him in competition the previous six years.

[18] He was the national flag bearer at three consecutive Olympics: in 1988 for the Soviet Union, in 1992 for the Unified Team, and in 1996 for Russia.

In addition to his success in wrestling, he was a sambo champion during his service in the Internal Troops, and participated in a strongman contest.

[42] He is listed as runner-up to David Koplovitz at the 1992 Wrestling World Cup, for while he won all of his matches at the event, his partner Andrey Grishin competed in the rest of the rounds, and so they did not accumulate enough ranking points to beat the American team.

[1] With his win, Karelin became the youngest Greco-Roman wrestler to become an Olympic champion at super heavyweight (130 kg) at the age of 21 years and two days.

[46] At the 1996 Summer Olympic Games in Atlanta, Karelin faced American Matt Ghaffari for the gold medal.

[2] Thus his only two losses at the senior level were in finals, those ultimately being the 1987 USSR Championships to Rostorotsky, and 2000 Summer Olympics to Gardner.

[39][57] Some argue, such as Finnish former wrestler Tuomo Karila, that Gardner should not have been awarded the point, and that Karelin should have won.

His coach was at first skeptical about a big but undeveloped boy, yet he accepted Karelin and motivated him for hard training, both in wrestling technique and physical strength.

When asked why he thought he was called that (referring to a biased opinion on his alleged PED use), Karelin noted that: "No one can completely believe that I am natural.

"[63] Karelin's daily training drills included hours of rowing and long runs through Taiga forest often with a large log on his back.

[64][65][66] He favored the overhead press and also used standard 2-pood kettlebells (32 kilograms (71 lb)) for arm exercises at a daily weight routine.

[71][17][72][73][69] Karelin also took part in a strongman competition, that being the 1991 European Hercules, and without prior preparation, he managed to place 8th.

The throw had long been in use by lighter wrestlers but not by heavyweights – because of the immense strength required to raise, spin and hit the mat with a 560+ lbs combined weight of both athletes (280+ of which resist desperately to the performed maneuver).

Karelin's ability to perform this throw against elite opponents weighing as much as 130 kg amazed other participants and observers of the sport.

[32][69] Furthermore, his incredible grip strength was described as being similar to that of "an anaconda", which allowed him to hold down his opponents and prevent them from escaping from his grasp.

[79] His strength, size, explosiveness, flexibility and agility led Joe Rogan to describe Karelin as a "human panther".

At the 1988 USSR Championships, Karelin won and also defeated Igor Rostorotsky in a rematch, despite suffering from a concussion and high temperature.

[82] Another injury occurred at the 1996 European Championships in Budapest, as he had torn the right pectoralis major muscle so badly that doctors predicted he would not be able to use his right hand for several months.

[18] On 21 February 1999, Karelin defeated Akira Maeda in a shoot wrestling contest put on by RINGS that drew a gate of over $1 million.

The match gained widespread media coverage, including mentions in The New York Times and Sports Illustrated.

His PhD is titled: "Methods of execution of suplex throw counters" (Russian: Методика проведения контрприемов от бросков прогибом), and "Integral training system for top-level wrestlers" (Russian: Система интегральной подготовки высококвалифицированных борцов).

[32][110][111][65][112] He is also seen as one of the most gifted athletes of all time due to his combination of explosiveness, strength, intellect, flexibility, and agility.

[122][123] He is a hidden playable character in the Japan-only, AKI Corporation-created, Nintendo 64 video game: Virtual Pro Wrestling 2.