She is president and chief executive officer of Ardmore Associates, an engineering consulting firm specializing in infrastructure, transportation, and construction management.
Previously, she served as chair of the U.S. Railroad Retirement Board, an independent agency in the executive branch of the federal government from 1998 to 2003. Thomas had worked for the City of Chicago, beginning as a research chemist for the Department of Water and then serving in a number of executive capacities: director of management services for the Department of Aviation from 1983 to 1989, director of personnel policy and utilization for the Department of Water from 1989 to 1992, deputy chief of staff to Mayor Richard M. Daley from 1992 to 1994, and commissioner of the Department of Buildings from 1994 to 1998.
She serves on the boards of trustees for the Chicago Zoological Society, the Chicago Archdiocese School Board, the Lyric Opera of Chicago and The Polk Brothers Foundation. She is also a member of The Chicago Network and the Big Shoulders Fund.
She received the Distinguished Alumna Award from the College of Arts and Sciences in 2002. She holds a master’s degree in physiology from the University of Illinois at Chicago and an honorary doctor of public administration degree from Boston College.
She is a member of the Marquette University President's Society.