She received a master's degree in music performance, graduating magna cum laude from Yale University.
Simonett worked in business litigation for Faegre & Benson and became a partner.
She was appointed a trial court judge in Minnesota's Fourth Judicial District.
In 1994 Governor Arne Carlson named her to be Chief Judge of the Minnesota Court of Appeals, succeeding Chief Judge Paul H. Anderson, who had been appointed to the Minnesota Supreme Court.
During her first year in office, Simonett was diagnosed with an incurable brain tumor.