Erin received a Bachelor of Arts, cum laude, from the University of Pennsylvania in 2003, with majors in Politics, Philosophy & Economics and Spanish (with distinction). She received a Masters from American University School of International Service in 2007 and a Juris Doctor, cum laude, from American University Washington College of Law in 2007. 

Erin was a law clerk at the District of Columbia Court of Appeals from 2008-2009; a litigation associate at Clifford Chance US LLP until 2014, where she focused heavily on pro bono matters including winning asylum for an individual fleeing state violence due to their political beliefs, representing a child with disabilities at a local school to ensure they received their needed educational supports, and filing briefs with the United States Supreme Court on the science regarding youth brain development to end the use of life without parole sentences for youth offenders; and Supervising Attorney of a human rights litigation law clinic at American University Washington College of Law until 2014.

Most recently, Erin served as an ethics lawyer for the federal judiciary, where she specialized in workplace accountability. Since 2018, she has also served as an Advisory Neighborhood Commissioner, a neighborhood-level elected position.