As a purple belt, he started teaching the art of Brazilian jiu-jitsu in Madrid and other cities of Spain.
He was Mirko Filipović’s sparring partner at that time and the Croat was the main reason for his debut in PRIDE.
Werdum then had the first loss in his MMA career, when he lost to Sergei Kharitonov via split decision in PRIDE 30.
He then faced former PRIDE Heavyweight Champion, Antônio Rodrigo Nogueira in the quarter-finals, losing via decision.
Werdum then had a short stint in 2 Hot 2 Handle, facing Alexander Emelianenko in a Heavyweight bout, and beating the Russian by submission via triangle choke armbar combination.
He began to train in Brazil at Chute Boxe Academy, becoming more aggressive and showing improvement in his striking, particularly in Muay Thai attacks.
In his next fight at UFC 90, Werdum was heavily favored to win but was knocked out in 1:20 of the first round via uppercut by debuting Junior dos Santos.
[16] Since Werdum was not contacted directly about the termination he had no idea he had been cut and initially denied the news of him no longer being in the UFC as just a rumor.
[10] He made his debut at Strikeforce: Carano vs. Cyborg on 15 August 2009, against fellow UFC veteran Mike "MAK" Kyle.
Werdum followed that up with a unanimous decision victory over Antônio "Bigfoot" Silva at Strikeforce: Fedor vs. Rogers.
[18] The victory ended Emelianenko's 28-fight unbeaten streak[18][19] while propelling Werdum's status up the Heavyweight rankings.
A rematch with Alistair Overeem took place on 18 June 2011, at Strikeforce: Dallas as part of an eight-man Heavyweight Tournament.
He has received some criticism for "pleading" Overeem to fight him on the ground in order to get into a position favorable to him due to his Brazilian jiu-jitsu background.
[25] Werdum coached opposite Antônio Rodrigo Nogueira on the second season of The Ultimate Fighter: Brazil.
Werdum faced Travis Browne at UFC on Fox 11 in a Heavyweight title eliminator bout.
[30][31] Despite being dropped by punches early on, he won the fight via TKO in the second round, becoming the new UFC interim Heavyweight Champion.
[42] Werdum lost the fight via knockout in the first round after rushing in with an attempted flurry of punches and was caught with a counter right hook, suffering his first defeat since June 2011.
[44] However, Rothwell pulled out of the fight on 11 August citing a knee injury and was replaced by former opponent Travis Browne.
[47] However the Nevada State Athletic Commission failed to approve Velasquez to fight, determining after physical examinations and interviews that he was unfit to compete.
[50] Although coming close to finishing Overeem in the third round, Werdum lost the bout via somewhat controversial majority decision.
[68] Werdum faced Alexander Gustafsson on July 26, 2020, at UFC on ESPN 14, the latter making his debut at heavyweight.
[72] On November 16, 2020, Werdum announced he had signed a multi-fight deal with the Professional Fighters League promotion and will compete in the 2021 PFL heavyweight tournament.
[74] On May 10, the New Jersey State Athletic Control Board announced that Ferreira's TKO win against Werdum was overturned to a no contest due to the controversy of the stoppage.
[79] Werdum was then booked to compete against in a rematch against Junior Dos Santos in a bare knuckle MMA fight at a Gamebred FC event on September 8, 2023.
Werdum was previously a Spanish-language commentator for the UFC and often comes to the octagon with the Spanish flag, as well as the Brazilian one.
[96] In January 2019, Werdum made the news when he and a lifeguard rescued drowning teenagers at a beach near his home in Torrance, California.
[97] In 2024, Werdum revealed that he had suffered brain lesions and scarring during his MMA career, and had suspected Chronic traumatic encephalopathy.