Judge Kerrigan was raised in New Hampshire and attended college in Boston. She received her BSN from Boston University and, after working as a nurse for several years in Boston, moved to Houston to work in the ENT Department at Baylor College of Medicine.
She then did private duty nursing to work her way through law school. She received her J.D. from the University of Houston Law Center, where she was Chief Justice of the Advocates and received the Law School's Distinguished Service Award. Upon graduation, Judge Kerrigan joined the law firm of Fulbright & Jaworski, LLP where she became a partner in 1992.