Due to his track record in Thai-Boxing, in 2000 Mahmoud was invited to a training camp for professional boxers at the famous Max Schmeling Gym in Berlin.

Charr was knocked down in the second round with a right hook, and he lost the bout by fourth-round technical knockout when it was stopped due to a cut received as a result of Klitschko's punches.

[7] Charr improved his record to 26-1 with wins over Oleksiy Mazikin, Dennis Bakhtov and Kevin Johnson, before challenging highly-ranked Alexander Povetkin on 30 May 2014 for the vacant WBC International title in Moscow, Russia.

[8] Charr's fight against Povetkin was the first of five consecutive bouts that subsequently took place in Russia, the last of which was a brutal one-punch fifth-round knockout defeat to Mairis Breidis on 22 August 2015 in Grozny, Chechnya.

[9] After improving to 30-4, Charr faced Alexander Ustinov for the vacant WBA (Regular) title in Oberhausen, Germany on 25 November 2017, and won by unanimous decision.

[14] Following extensive litigation with the WBA, Charr's title was restored on 31 August 2023 as part of a court settlement, and he was ordered to defend against Jarrell Miller by 14 October of that year, with the winner to face the next highest contender.

In 2015, an altercation at a kebab shop in Essen, Germany led to a drive-by shooting which left Charr shot four times in the abdomen and forced to undergo emergency surgery that night to save his life.