Throughout her career, Briggs has been actively involved in the feminist and LGBTQ movements, Latin American solidarity politics, union organizing, and AIDS activism. She was an organizer of the Second National March on Washington for Lesbian and Gay Rights in 1987, and, from 1989 to 1991, she was a reporter for "Gay Community News", reporting on subjects ranging from reproductive rights in South Africa and Central America to Boston LGBT politics. She was a founder and organizer of the Tepotzlan Conference and volunteered as a border Samaritan during her time at the University of Arizona. In 2016 and 2017, Briggs served on the Executive Council of the American Studies Association. Her writing about the Adoptive Couple v. Baby Girl 2013 Supreme Court case has been featured on local and national sites.