Maso is a graduate of the Howard University School of Law, where he was on the Huver I. Brown Trial Advocacy National Moot Court Team. After graduation, Maso served as a law clerk, and later prosecutor, for the Baltimore City State's Attorneys Office. He then moved to the Howard County State's Attorney's Office before arriving at the Prince George's County State's Attorney's Office, where he serves as a trial lawyer in the Strategic Investigations/Homicide Unit. Maso was also named as a "Top 40 Under 40" by National Black Laywers, was a MSBA Leadership Academy Fellow, and has been named as a Bar Fellow for the Maryland Bar Foundation.