G.J. Stillson MacDonnell was born in Danbury, Connecticut in 1947 and graduated from New York University. She received a law degree from the University of Connecticut in 1973. In 1974 she started an independent practice in Hartford and 5 months later joined a Hartford law firm. She was founder and attorney for Hartford Rape Crisis Service; chair of Coalition of Connecticut, an organization concerned with women's issues; attorney and board member of Connecticut Feminist Federal Credit Union in New Haven. MacDonnell frequently worked as unpaid lobbyist for feminist organizations and testified before Connecticut legislator for the ERA, abortion rights, divorce, sexual assault laws, and gay rights. In 1969 she a joined larger firm working with legal issues of employee benefits.