A cum laude graduate of the Harvard Law School, Jill Sullivan began her trial practice in 1996 as an attorney at Latham & Watkins, where she was trained and mentored by Joseph J. Wheeler. During that time, Ms. Sullivan successfully represented business clients in complex commercial cases through every phase of their litigation, including trial and appeals. In 2004, she moved to her hometown of Kansas City, Missouri, where she practiced business litigation with Sonnenschein Nath & Rosenthal LLP (now SNR Denton).

In 2005, Ms. Sullivan returned to San Diego to start the firm of Chapin Wheeler LLP with Ed Chapin and Jay Wheeler. From the inception of the firm, Ms. Sullivan has focused on representation of plaintiffs in business and employment litigation. Her litigation and trial experience includes matters involving fraud, breach of contract, trademark infringement, tortious interference, libel, misappropriation of trade secrets, legal malpractice, breach of fiduciary duty, insurance bad faith, financial elder abuse, civil RICO, and unfair competition, in addition to employment disputes on behalf of plaintiffs and defendants. Ms. Sullivan became a partner at Chapin Wheeler LLP in 2008, and became a named partner at Chapin Fitzgerald Sullivan in 2010.

Ms. Sullivan served on the Board of Directors of the Consumer Attorneys of San Diego in 2008 and 2009. She currently chairs the San Diego Bar Association's Jay Wheeler Civility Seminar Committee, and in 2008 was a member of the San Diego Bar Association's Committee on Civility, Integrity, and Professionalism in the practice of law. She is a Barrister in the Enright Inn of Court, which is a San Diego Chapter of the American Inns of Court, and is a member of the Association of Business Trial Lawyers, the San Diego County Bar Association, the Federal Bar Association, and the American Bar Association. Ms. Sullivan devotes her pro bono efforts to the cause of abused and neglected children, leading the firm's participation in Voices for Children, a program advocating for abused and neglected children. She also volunteers her time reading to elementary school children at Porter Elementary School in San Diego as part of the San Diego County Bar Association's Porter Readers program. She is admitted to practice in California and Missouri.

Ms. Sullivan was recognized by the San Diego Daily Transcript in 2010 as one of the "Top Attorneys" in San Diego for corporate litigation. In 2011, she was named a San Diego "Super Lawyer" in the area of general litigation, a distinction that is awarded by peer vote and is highlighted in Super Lawyers magazine.