He has been performing at a professional level since 2012, and he is also known for his participation in the tournaments of fighting organizations Bellator MMA and Rizin FF.

[3] Albrektsson made his debut in the Polish organization MMA Koszalin and won his first match via finish in the second round.

[4] On September 25 of the same year, Karl faced Valentin Moldavsky at Rizin World Grand Prix 2016: 2nd RoundMoldavsky was the first to defeat Albrektsson in the latter's professional career.

[5] Just over ten months later, it was time for Karl's next bout on July 30, 2017, at Rizin Fighting World Grand Prix 2017 Opening Round Part 1.

[12] Albrektsson debuted in the organization on October 25, 2019, at Bellator 231 against former Light heavyweight Phil Davis in the co-main bout.

[14] Albrektsson faced Viktor Nemkov, the brother of his previous opponent, at Bellator 257 on April 16, 2021.

[17] After Anglickas replaced Anthony Johnson in the LHW Grand Prix, Albrektsson instead faced Dovletdzhan Yagshimuradov.

[19] As the first fight of his new multi-fight, multi-year contract, Albrektsson faced Karl Moore on September 23, 2022, at Bellator 285.