Native to Belleville, Illinois (part of Greater St. Louis), McCaskill and was raised by her great aunt and her four sons.
[4] McCaskill made her professional debut on August 22, 2015 with a technical knockout (TKO) victory against Tyrea Nichole Duncan at the Horseshoe Casino in Hammond, Indiana.
[7] On October 6, 2018, McCaskill defeated two-weight world champion Érica Farías for the WBC female super lightweight title at the Wintrust Arena in Chicago, Illinois, winning her first world title by unanimous decision, with the judges' scorecards reading 98–92, 97–93 and 96–94.
[9] On October 12, 2019, McCaskill defended her unified titles in a rematch against Érica Farías at the Wintrust Arena in Chicago.
[14] Early 2024 it was announced that McCaskill would defend her WBC, WBA, IBO and Ring welterweight titles against Ivana Habazin on April 20, 2024 in Croatia.