Pereira is the only known fighter to be a two-division world champion in MMA and kickboxing and is regarded as one of the greatest combat athletes of all time.

[11][12] Growing up in a favela, Pereira dropped out of middle school to begin working as a bricklayer's assistant[13] and later in a tire shop.

[15] Before becoming a prominent figure in kickboxing and mixed martial arts, Alex Pereira had a notable amateur boxing career in Brazil.

He reportedly competed in 28 amateur boxing matches, achieving a record of 25 wins, all by knockout, with just 3 losses.

[16] Pereira’s signature power, particularly his devastating left hook, became evident early in his amateur career, as seen in viral footage showcasing multiple knockouts, including an instance where he knocked an opponent out of the ring.

Ryan Garcia, impressed by Pereira’s ability, publicly expressed interest in training with him, highlighting the difficulty of finishing opponents in amateur boxing.

Pereira’s striking abilities in the amateur ranks have also drawn admiration from other elite boxers, further emphasizing his versatility across multiple combat sports disciplines.

In 2014 he made his Glory debut having won the Glory 14: Zagreb - Middleweight Contender Tournament in Zagreb, Croatia on 8 March 2014, beating Dustin Jacoby by first-round knockout in the semi-finals and Sahak Parparyan by majority decision in the final.

[20][21] He lost to eventual champion Artem Levin by unanimous decision in the quarter-finals to exit the tournament.

[27] During this run Pereira achieved his most famous victories, defeating the future UFC Middleweight champion Israel Adesanya twice: once by unanimous decision, and once by a counter left hook KO.

[40] After winning the Interim Light Heavyweight Championship, Pereira opted to defend his middleweight title against Ertugrul Bayrak at Glory Collision 2 on 21 December 2019.

[42] Pereira won the fight by split decision, becoming the first fighter in GLORY history to simultaneously hold two belts at the same time.

Pereira was deducted one point in round 4 due to repeated clinching, which was seen by many as a controversial decision by the referee.

[48] He continued at Jungle Fight subsequently racking up two straight victories against Marcelo Cruz and Marcus Vinicius Silveira, with a KO and TKO respectively.

Pereira announced he had signed a contract to face Diego Henrique da Silva in the Brazilian edition of Dana White's Contender Series on August 10, 2018.

[50] On 22 October 2020, news surfaced that Pereira had signed a contract with Legacy Fighting Alliance and he then made his promotional debut against Thomas Powell on 20 November 2020.

[68] For comparison, his longtime rival Israel Adesanya typically weighed 196 pounds on fight night.

[79] On two weeks notice, replacing the main event bout between Michael Chandler and Conor McGregor, who was injured, Pereira faced Jiří Procházka in a rematch on 29 June 2024, at UFC 303.

[92] The nickname was given to him by his first kickboxing trainer Belocqua Wera, who was also responsible for helping Pereira discover his indigenous ancestry.