[6][7] Davis is trained by Calvin Ford who was the inspiration for the character Dennis "Cutty" Wise on the hit HBO television series, The Wire.

[12] Davis made his debut at the age of 18 on February 22, 2013, against Desi Williams, who had a professional record of 0 wins and 4 losses, all by stoppage.

[14] On May 22, 2015, at The Claridge Hotel in Atlantic City, New Jersey, Davis scored a technical knockout (TKO) against Alberto Mora (5–3, 1 KO) 1 minute 14 seconds into the fight.

[15] On September 12, 2015, at the MGM Grand Garden Arena in Las Vegas on Showtime as part of the Floyd Mayweather Jr. vs. Andre Berto undercard, Davis defeated Recky Dulay (8–1, 5 KOs) in only 94 seconds.

[16] On October 30, 2015 , at The Venue at UCF in Orlando, Florida, on Bounce TV, Davis defeated veteran 38-years-old former featherweight title holder Cristobal Cruz (40–18–4, 24 KOs).

[17] On December 18, 2015, at the Palms Casino Resort in Las Vegas on Spike TV, Davis scored a ninth-round KO over Luis Sanchez (17–4–1, 5 KOs).

[18] On April 1, 2016, at the D.C. Armory on Spike TV, Davis defeated Guillermo Avila (16–5, 13 KOs) by KO in the sixth round.

[19][20] On June 3, 2016, at the Seminole Hard Rock Hotel and Casino in Hollywood, Florida, as part of a Premier Boxing Champions card, Davis knocked out Mario Antonio Macias (28–18, 14 KOs) with his first punch of the fight, which lasted only 41 seconds.

[21] On November 15, 2016 ESPN announced that Davis would challenge for the IBF super featherweight title against undefeated José Pedraza (22–0, 12 KOs) on January 14, 2017, at the Barclays Center in New York on Showtime.

[23] After the fight, Davis said that he had studied the early career of his promoter and mentor, Floyd Mayweather Jr., in order to stay composed.

[31] According to TMZ Sports in early July 2017, it was reported that Davis would feature in the co-main event of Floyd Mayweather Jr. vs. Conor McGregor on August 26, 2017, at the T-Mobile Arena in Paradise, Nevada.

[32] On July 29, The Ring magazine reported that Davis would likely defend his IBF title against former WBO champion Román Martínez, whose last fight was a KO loss to Vasyl Lomachenko in June 2016.

[33] On August 10, Ringtv reported that Davis would instead fight unbeaten prospect Francisco Fonseca (19–0–1, 13 KOs), who at the time was ranked number 7 by the IBF.

[40] On November 15, 2017, Leonard Ellerbe, CEO of Mayweather Promotions announced that Davis would be making his in ring return in the first quarter of 2018 alongside stablemate Badou Jack.

[42] On January 24, 2018, Showtime announced that Davis would next appear on television on the undercard of Broner vs. Vargas on April 21 at the Barclays Center in New York.

[49] In November 2018, Davis announced that he would defend his WBA title in February 2019 against former titlist Abner Mares (31–3–1, 15 KOs) in Southern California.

[57] His win marked the first time a native of Baltimore had returned to the city to defend a world title since featherweight champion Harry Jeffra defeated Spider Armstrong in 1940.

[65] In his second fight headlining a Showtime PPV, Davis moved up to the super lightweight division for the first time in his career to face WBA (Regular) champion Mario Barrios on June 26, 2021, at the State Farm Arena in Atlanta, Georgia.

[69] On October 6, 2021, Davis announced that he would be facing his mandatory challenger, Rolando Romero on December 5 at the Staples Center in Los Angeles on Showtime PPV.

[70] However, Romero was pulled from the bout due to sexual assault allegations made against him, and was subsequently replaced with Isaac Cruz.

[76] On February 24, 2023, it was announced that Davis would face Ryan Garcia in a catchweight bout on April 22, in Las Vegas, Nevada.

[79] Davis defended his WBA lightweight title against Frank Martin on June 15, 2024 at MGM Grand Garden Arena in Las Vegas.

[82] Davis was scheduled to defend his WBA lightweight title against Lamont Roach Jr. at Toyota Center in Houston, TX on December 14, 2024.

[90][91] On August 21, 2021, Davis was on board a Gulfstream 4 that suffered a nosewheel collapse and subsequently skidded off the runway at Fort Lauderdale Executive Airport.

At the court, Anthony Wheeler, a childhood friend, complained that Davis punched him on the side of the head with a "gloved fist".

The incident occurred at the Watsco Center at the University of Miami during a basketball game where he was seen grabbing the woman's shirt "with his right hand close to her throat" and dragged her to a separate room.

[100] On March 22, 2021, he was indicted on fourteen counts for allegedly causing a serious car crash after running a red light after a November 2020 birthday party in downtown Baltimore.

[101] On February 16, Davis accepted a plea deal that saw him plead guilty to leaving the scene of an accident involving bodily injury, failing to notify an owner of property damage, driving on a suspended license and running a red light.

[104] On December 27, 2022, days before he was due to fight Héctor García, Davis was arrested and jailed in Florida on a charge of battery domestic violence.

Police observed an abrasion on the inside of the woman's lip, with Davis accused of striking her with a "closed hand type slap.