Davis was a young girl when she got interested in martial arts. She was big fan of Action movies starred by Jackie Chan, Jet Li and Jean-Claude Van Damme and was a big fan of boxing and later MMA. She was a youngster when she decided to start practicing martial arts and was around age of 16 when she started jujutsu and BJJ at age of 18.
Davis made her mixed martial arts debut on April 7, 2007, at UCW 7: Anarchy. She was defeated by former Strikeforce champion Sarah Kaufman via TKO in the third round. On December 14, 2007, Davis defeated Valérie Létourneau by split decision at TKO 31: Young Guns. The fight was the second women's bout in TKO history. Davis faced Liz Carreiro at FFF 4: Call of the Wild on April 3, 2008. She won the fight by unanimous decision.
On January 23, 2009, Davis faced Tara LaRosa at Extreme Challenge: The War at the Shore. She lost by TKO in the third round after the ringside doctor stopped the fight due to a cut. The fight was voted as the 2009 Women's MMA Fight of the Year. Davis defeated Molly Helsel by unanimous decision after five rounds at Raging Wolf 5: Mayhem In The Mist on October 10, 2009, to become Raging Wolf Women's Flyweight Champion.
On March 27, 2010, at FCF 40, Davis replaced Jennifer Tate in the second round of the Freestyle Cage Fighting Women's Bantamweight Grand Prix. She faced submission specialist Shayna Baszler and was defeated by unanimous decision. Davis was scheduled to face Elaina Maxwell at Raging Wolf 7: Mayhem In The Mist 3 on May 8, 2010, but Maxwell pulled out of the fight due to an injury. Davis defended her Raging Wolf title against Tonya Evinger instead. She won the fight and retained her title via rear-naked choke submission in the third round.
Davis' next fight was against Elaina Maxwell at Raging Wolf 9 on August 28, 2010. This fight was originally for the Raging Wolf Women's Flyweight Championship, but Maxwell was unable to make the 135 lbs weight limit, so the fight was changed to a non-title, three-round contest. Davis was defeated by unanimous decision. Davis successfully defended her title in a rematch with Evinger at Raging Wolf 10 on November 6, 2010. She once again submitted Evinger with a rear-naked choke. She was scheduled to challenge Shayna Baszler in a title fight rematch at The Cage Inc.: Battle At The Border 10 on July 30, 2011. However, the fight was cancelled after Davis signed with Strikeforce.
Davis made her Strikeforce debut on July 30, 2011, against Julie Kedzie. She won the fight via unanimous decision. She faced Amanda Nunes on September 10, 2011, on the Strikeforce Grand Prix Semifinals card. She won the fight via TKO late in the second round. On January 7, 2012, it was announced that Davis would face Sarah Kaufman in a rematch at Strikeforce: Tate vs. Rousey on March 3, 2012, in Columbus, Ohio. She lost the back and forth bout via a very close majority decision.
Davis faced Hitomi Akano at Invicta FC 2: Baszler vs. McMann on July 28, 2012. She defeated Akano by submission due to a rear-naked choke in the second round and earned a submission of the night bonus. Davis faced Shayna Baszler in a rematch at Invicta FC 4: Esparza vs. Hyatt on January 5, 2013. Davis won the fight via technical submission due to a rear-naked choke in the third round. The bout was named Fight of the Night.
On Feb 12, 2013, it was announced that both Davis and Sara McMann were signed to the UFC. Davis faced Rosi Sexton in her UFC debut at UFC 161 on June 15. She won the back-and-forth fight via unanimous decision. In her second UFC bout, Davis faced Liz Carmouche on November 6, 2013, at UFC Fight Night 31. She won the fight via unanimous decision. cDavis faced Jessica Eye on February 22, 2014, at UFC 170. Davis won the fight via split decision.
Davis faced UFC Women's Bantamweight Champion Ronda Rousey for the belt at UFC 175 on July 5, 2014. She lost the fight via knockout sixteen seconds into the first round.
Davis faced Sarah Kaufman for a third time at UFC 186 on April 25, 2015. After losing the first round due to Kaufman's dominating striking, she won the fight via submission in the second round. Following this fight, Davis took time off due to pregnancy.
On October 19, 2016, it was announced that she would be making her return at The Ultimate Fighter 24 Finale on December 3, 2016 against Sara McMann She lost that fight via arm-triangle submission in the second round.
Davis next faced Cindy Dandois on April 22, 2017 at UFC Fight Night: Swanson vs. Lobov. She won the fight by unanimous decision.Raging Wolf MMA
Raging Wolf Women's Bantamweight Championship (One time)
Fight of the Night (One time) vs. Shayna Baszler
Ultimate Fighting Championship
First Canadian Woman to Fight in the UFC
First Canadian Woman to Win a Fight in the UFC
Women's MMA Awards
2009 Fight of the Year vs. Tara LaRosa
2012 Fight of the Year vs. Sarah Kaufman