[6] Bader attended Arizona State University on a wrestling scholarship, where he was college teammates with former UFC Heavyweight Champion Cain Velasquez and CB Dollaway.

At the finale, Bader defeated Magalhães by way of a quick, first-round knockout, earning the title of "The Ultimate Fighter" and winning the traditional "six-figure UFC contract".

An overhand right dropped Magalhães, and Bader followed up with strikes on the ground to take the win, less than halfway through the first round.

[9] The fight was mainly dominated by Bader, who scored with a powerful attack of combinations standing and controlled the grappling, en route a unanimous decision victory (30–27, 29–26, and 30–27).

Along with Jesse Forbes, CB Dollaway, Eric Larkin and Aaron Simpson, Bader left Arizona Combat Sports to train at their newly opened gym Power MMA And Fitness.

[12] Four months after his victory over Nogueira, Bader fought fellow rising prospect Jon Jones on February 5, 2011, at UFC 126,[13] where he received the first loss of his MMA career after tapping out to a modified guillotine choke in the second round.

[21] Bader faced former title challenger Vladimir Matyushenko on January 26, 2013, at UFC on Fox 6.

[26] The bout with Teixeira eventually took place on September 4, 2013, in the main event at UFC Fight Night 28.

[37] Bader was expected to face Daniel Cormier on June 6, 2015, at UFC Fight Night 68.

[38] However, on April 28, 2015 it was announced that Cormier had been removed from the fight in favor of a matchup with Anthony Johnson on May 23, 2015 at UFC 187.

[44] He won the fight via knockout in the second round and was awarded a Performance of the Night bonus.

[45][46] Bader faced Antônio Rogério Nogueira in a rematch on November 19, 2016, in the main event at UFC Fight Night 100.

After the main event, Bader entered the cage and it was announced he would face Muhammed Lawal at Bellator 180 on June 24, 2017.

However, Lawal pulled out of the fight and Bader faced Bellator Light Heavyweight champion Phil Davis in a rematch.

[55] Bader claimed the title by winning via knockout 35 seconds into the first round, thus becoming the first simultaneous two-weight champion in Bellator history.

[57][58] On July 11, 2019, it was announced that Bader is set to make his first heavyweight title defense against Cheick Kongo.

[60] Bader was signed to defend his light heavyweight title against Vadim Nemkov at Bellator 242 on May 9, 2020.

[63] On February 9, 2021, it was announced that Bader would be participating in the Bellator Light Heavyweight World Grand Prix.

[64] After Machida showed early success in the first two rounds on the feet via kicks, Bader soon controlled the rest of the bout on the ground, winning via a unanimous decision.

[65] In the semi-finals of the Grand Prix, Bader faced Corey Anderson on October 16, 2021 at Bellator 268.

[70] As the first bout of his new four-fight contract, Bader defended his title in a rematch against Cheick Kongo on May 6, 2022 at Bellator 280.

[75] Bader was set to defend his title in a rematch against Linton Vassell on October 7, 2023 at Bellator 300.