[2] Foster bounced back from his second professional loss with a first-round technical knockout of Andrew Goodrich on 29 December 2017 and a majority decision win against Kaylyn Alfred on 20 January 2018, with both fights taking place at lightweight.
[3] Foster was booked to face the unbeaten WBC Silver super featherweight champion Jon Fernandez, in the main event of the "ShoBox: The New Generation" series, which took place on 21 September 2018.
[6] Foster was scheduled to fight Jesus Bravo for the vacant WBA Fedecentro super featherweight title on 17 July 2019, at the Gimnasio Nacional Eddy Cortés in San Juan, Puerto Rico.
[7] Foster made his first WBC Silver title defense against Alberto Mercado on 5 December 2019, at the Terminal 5 in New York City.
[9] Foster made his second WBC Silver title defense against the veteran Miguel Roman on 19 November 2020, after an eleven-month absence from the sport.
[10] Some minor controversy occurred prior to the fight, as it was discovered by Foster's head coach Bobby Benton that the padding was removed from Roman's gloves.
[11] Foster won the fight by a ninth-round knockout, forcing a referee stoppage with a flurry of punches at the 0:58 minute mark.
[16] The sanctioning body permitted Vargas to challenge for the vacant championship, while holding a belt a weight class lower, following the breakdown of his negotiations with the WBA featherweight titleholder Léo Santa Cruz.
[23][24] On February 16, 2024, Foster was scheduled to make the second defense of his title against Abraham Nova at The Theater at Madison Square Garden in New York.
[26][27] Foster was scheduled to make the third defense of his WBC super featherweight title against Robson Conceicao at Prudential Center in Newark, New Jersey on July 6, 2024.
[29][30] On August 29, 2024 it was reported that Foster would challenge Robson Conceição for his WBC super featherweight title in a championship rematch on November 2, 2024 in Verona, New York.