A recipient of an International Rotary Fellowship, Simmons continued her legal studies at Durham University in England, focusing on the emerging European Economic Community, prior to settling in San Antonio.
Simmons practiced law at Akin Gump Strauss Hauer & Feld LLP in San Antonio, where she specialized in complex commercial litigation.
Based on her proven track record[citation needed] on the district bench, she was selected to serve on the Fourth Court in May 2005 and then elected in 2006.
As of 2017[update], she was seeking election to the Fourth Court of Appeals place 5 currently held by Justice Angelini, who has announced her retirement at the end of her term.
A recipient of the State Bar of Texas Presidential Citation, she is a member of the Pattern Jury Charge Committee.