Keely McCabe completed her undergraduate education at Hanover College in Hanover, Indiana. Before going to law school, Keely served in the AmeriCorps in a program called City Year. In City Year, Keely provided in-class support to students during the school day and helped to run an after school program. After her service year, Keely started law school at Florida Coastal School of Law in Jacksonville, Florida.

Keely spent most of her legal career as an administrative adjudicator conducting administrative hearings. Early in her career, Keely conducted unemployment insurance appeals hearings for the State of Indiana Department of Workforce Development. Keely later conducted driver, business licensure, and rule promulgation hearings for the Colorado Department of Revenue. In her final position as an administrative adjudicator, Keely served as an Administrative Law Judge for the Colorado State Personnel Board. In addition to conducting hearings and issuing initial decisions related to employment within the State Personnel System, Keely facilitated settlement discussions and wrote preliminary recommendations to the State Personnel Board.