Upon graduating from New England Law, Judge Muirhead worked for the City of Boston as associate counsel for the Boston Rent Equity Board, defending Board decisions in the Massachusetts trial and appellate courts. When she left the City of Boston, Judge Muirhead worked for several Massachusetts law firms in all aspects of housing and property law; including, but not limited to, real estate development, representation of organization of unit owners at residential condominiums, construction defect litigation and insurance defense. She tried and successfully defended the matter of Boston Housing Authority v. Guirola, 410 Mass. 820 (1991), which was heard in the Supreme Judicial Court on its own motion. The case was a matter of first impression.
Judge Muirhead sits on the Board of Directors of United Cerebral Palsy of Metro Boston and Louisa May Alcott's Orchard House. She also served as president of the Community Associations Institute of New England, chaired committees of the Massachusetts Bar Association and served on panels for MCLE.