McMann announced in late 2010 that she had signed a three-fight contract with
Strikeforce. She planned to fight at 135 pounds. However, she did not sign on with the promotion due to an extension clause in the contract. McMann was first scheduled to make her professional mixed martial arts debut on November 14, 2010 in
Jamaica, but the event was cancelled due to safety problems with the cage. She then had more fights fall apart after opponents backed out, including a scheduled April 30, 2011 fight against Mariah Johnson. On May 28, 2011, McMann made her pro MMA debut at Universal Cage Combat: Revolution. She defeated Christina Marks by submission in the first round. McMann faced fellow Olympian Julie Malenfant at Blackeye Promotions 4 on June 17, 2011. McMann defeated Malenfant by TKO early in the first round. McMann faced
Tonya Evinger at Titan Fighting Championships 19 on July 29, 2011. The fight served as the co-main event. McMann defeated Evinger by unanimous decision. McMann returned to ProElite to face
Hitomi Akano at
ProElite 3 on January 21, 2012. She defeated Akano by unanimous decision.
Invicta Fighting Championships On April 28, it was announced that McMann would face
Shayna Baszler in the main event of Invicta Fighting Championships 2. The event took place on July 28, 2012. McMann defeated Baszler via unanimous decision and the bout was named fight of the night. The bout was a title eliminator, with the winner scheduled to face the winner of Alexis Davis vs. Hitomi Akano.
Strikeforce On September 4, 2012, it was announced McMann had signed with Strikeforce. She was expected to debut at
Strikeforce: Cormier vs. Mir against former bantamweight title challenger
Liz Carmouche, but the event was cancelled.
Ultimate Fighting Championship In February 2013, McMann officially joined the
Ultimate Fighting Championship (UFC). It was rumored she turned down a fight with then-title holder Ronda Rousey. However, this was false information and no such fight was offered or even presented to McMann at the time. She became the third female to earn a victory in the UFC by defeating
Sheila Gaff at
UFC 159. McMann was slated to face former Strikeforce champion
Sarah Kaufman on August 28, 2013 at
UFC Fight Night 27. However, McMann withdrew from the bout for, at the time, undisclosed personal reasons. In January 2015, she disclosed that the reason for withdrawing was due to her father battling aggressive
lymphoma. McMann faced
Ronda Rousey for the
UFC Women's Bantamweight Championship at
UFC 170. She lost the fight by TKO after getting knocked down with a knee to the body. This stoppage created controversy, with many sports writers and attendants finding it premature. McMann faced promotional newcomer
Lauren Murphy at
UFC Fight Night 47 on August 16, 2014. McMann won the fight by split decision. McMann faced
Miesha Tate at
UFC 183 on January 31, 2015. Despite a strong first round, she lost by majority decision. McMann faced
Amanda Nunes on August 8, 2015 at
UFC Fight Night 73. She lost the fight via submission in the first round. McMann faced
Jessica Eye at
UFC Fight Night 88 on May 29, 2016. She won the fight via unanimous decision. McMann faced
Alexis Davis on December 3, 2016 at
The Ultimate Fighter: Tournament of Champions. McMann won via submission in the second round. This fight earned her a
Performance of the Night award. McMann was expected to face
Liz Carmouche at
UFC Fight Night 105, on February 19, 2017. However, Carmouche was forced to pull out of the fight due to injury and will be replaced by newcomer
Gina Mazany. McMann won the fight via submission early in the first round. McMann was originally expected to face
Ketlen Vieira at
UFC 214 on July 29, 2017. However, the fight was moved to
UFC 215. She lost the bout via arm-triangle choke submission in the second round. McMann faced
Marion Reneau on February 24, 2018 at
UFC on Fox 28. After dominating the first round, McMann was knocked down and submitted by Reneau in the second round. After a year hiatus due to maternity leave, McMann was scheduled to face
Nicco Montaño on July 13, 2019 at
UFC on ESPN+ 13. However, McMann pulled out of the bout citing an injury in mid-June and was replaced by
Julianna Peña. McMann faced
Lina Länsberg on January 25, 2020 at
UFC Fight Night 166. She won the fight via unanimous decision. McMann was scheduled to face
Aspen Ladd on June 27, 2020 at
UFC on ESPN: Poirier vs. Hooker. However, Ladd suffered a training injury, torn both her
ACL and
MCL and was forced to withdraw from the event. McMann was expected to face
Julianna Peña on January 16, 2021 at
UFC on ABC 1 before being pushed back a week later to
UFC 257 on January 24, 2021. McMann lost the fight via submission in round three. McMann was scheduled to face
Ketlen Vieira on August 28, 2021 at
UFC on ESPN 30. However, McMann announced in mid August that a "reinjury" forced her out of the bout. McMann faced
Karol Rosa on March 26, 2022 at
UFC on ESPN 33. She won the fight by unanimous decision. McMann was scheduled to face
Aspen Ladd on August 13, 2022, at
UFC on ESPN 41. However, Ladd was
tested positive for COVID-19 and she was forced to withdraw from the event, and they were rescheduled for
UFC Fight Night 210 on September 17. At the weigh-ins, Ladd weighed in at 138 pounds, two pounds over the bantamweight non-title fight limit. As a result the bout was scrapped. The cancelled bout against Ladd was counted as her last bout of her contract and she was paid her show money, with McMann now being a free agent and exploring potential possibilities.
Bellator MMA On December 27, 2022, it was announced that McMann had signed with the
Bellator MMA. McMann made her promotional debut against
Arlene Blencowe on April 21, 2023 at
Bellator 294. She won the bout via unanimous decision. McMann faced
Leah McCourt on October 7, 2023 at
Bellator 300. She lost the fight via ground and pound TKO in the first round. ==Personal life==