In 1994, when he was 14 years old, he had finally had enough and started lifting weights to put on muscle and, he hoped, to help him deal with these bullies.

[5] Enrolling at the police academy in Minsk, Arlovski combined his interest in a career in law enforcement with his growing martial arts participation by taking up the required police defense course in Sambo and quickly showed himself to be a highly competent Sambo opponent.

[1] Arlovski began taking a greater interest in other martial arts, studying kickboxing and developing his striking skills to complement his Sambo-based grappling abilities.

At the age of 20, Arlovski began his professional MMA career at the Mix Fight M-1 in St Petersburg, Russia on 9 April 1999 facing Viacheslav Datsik.

Arlovski made his Ultimate Fighting Championship debut at UFC 28, defeating Aaron Brink by submission.

Arlovski ended up facing Wesley Correira, winning the fight via TKO in the second round.

[7][8] On 12 August 2005, the UFC announced that it now recognized Arlovski as the undisputed heavyweight champion, as Frank Mir had not fully rehabilitated from his motorcycle accident.

"[9] Not too long after it was revealed Sylvia had sustained an injury as he fainted at his hotel room and upon hospital examination, doctors discovered a concussion.

[10] Arlovski made his next appearance on 30 December 2006, at UFC 66 against Brazilian Jiu-Jitsu black belt Márcio Cruz.

When the referee intervened, he decided, because of Cruz's insistence, to allow both fighters to stay on the ground as opposed to standing them up, as is the general practice.

Arlovski fought PRIDE veteran and two-time world Brazilian Jiu-Jitsu champion Fabrício Werdum at UFC 70, winning by unanimous decision.

After 11 months of inactivity, Arlovski made his return to the octagon at UFC 82 and defeated Jake O'Brien by TKO in round two.

Arlovski won the fight via KO in the second round and in the process became the only man to ever finish Nelson in his MMA career at that point.

[14] In January 2009, Arlovski faced the last reigning PRIDE heavyweight champion Fedor Emelianenko at Affliction: Day of Reckoning.

[17] Arlovski was a featured attendee at Strikeforce: Emelianenko vs. Rogers, where he was mobbed by a crowd of local Chicago fans.

[19] Arlovski was defeated by Sergei Kharitonov via KO on 12 February 2011, as part of the Strikeforce Heavyweight Grand Prix Tournament.

Arlovski dedicated himself to training exclusively with Greg Jackson in New Mexico to refocus on his MMA career and make the necessary changes to get back on track.

[21] After several months of grueling training schedule in New Mexico with Greg Jackson and the likes of Jon Jones, Shane Carwin, and Travis Browne, Arlovski headlined ProElite 1 on 27 August at the Neal S. Blaisdell Center in Honolulu, Hawaii against heavyweight Ray Lopez.

[23] Arlovski faced off against veteran of over 300 fights Travis Fulton at ProElite 2 in November, serving as the co-main event.

Arlovski had knocked Tim Sylvia down with punches before he landed the illegal kicks that caused the referee to stop the fight.

Controversy arose after the fight when it was revealed that multiple rounds exceeded the five-minute time limit.

[38] On 24 April 2014, it was confirmed by multiple MMA media websites that Arlovski had been granted his release from WSOF to return to UFC.

Post-fight, Joe Rogan revealed in the commentary that Arlovski came close to withdrawing from the fight due to a calf injury in training.

[4] Arlovski faced Júnior Albini at UFC Fight Night: Poirier vs. Pettis on 11 November 2017 in Norfolk, Virginia.

In the fight, Arlovski landed a career-best 4 takedowns, more than his entire career total up to that time (3) combined.

[70] The result was overturned to no contest after Harris tested positive for prohibited substance LGB4033, a selective androgen receptor modulator (SARM).

[74] He won the fight via unanimous decision and set the all-time record for UFC heavyweight victories at 17.

[79] However, on April 9, Dana White, the president of UFC announced that this event was postponed due to the ongoing Coronavirus pandemic.

Arlovski did a public service announcement against dog fighting featuring Maximus and calling it inhumane and torture.

[112] In 2018, Arlovski had a small role as a mob enforcer opposite Denzel Washington in the opening scene of The Equalizer 2.