Riddle earned a degree with honors in mathematics at Indiana University in 1971. In 1974, she earned a law degree from the Indiana University School of Law. She received an honorary Doctor of Humane Letters from Saint Joseph College.
Staff attorney Indiana Legislation Service Agency, Indianapolis, 1974-1978, legal counsel, 1978-1979. Deputy Corporate Counsel City of New Haven, 1980-1983. Counsel to attorney general State of Connecticut, Hartford, 1983-1986, deputy attorney general, 1986-1989, acting attorney general, 1989, attorney general, 1989-1991, judge Superior Court, 1991-1993.
Association executive, senior vice president, general counsel National Multi-Housing Council, National Apartment Association, 1995—2003. Chief of staff to Senator Joseph I. Lieberman United States Senate, Washington, since 2003. Assistant counsel state majority Connecticut General Assembly, Hartford, 1979, legal research assistant to professor Yale University, New Haven, 1979.
Legal counsel committee on law revision Indianapolis State Bar Association, 1979. Member Chief Justice's Task Force on Gender Bias, Hartford, 1988-1990. Member ethics and values committee Indiana Sector, Washington, 1988-1990.
Co-organizer Indiana Continuing Legal Education Forum Institute Legal Drafting Legislature and Private Practice. International Women's Year panelist Credit Laws and Their Enforcement. Member Attorney General's Blue Ribbon Commission, Chief Justice's Committee Study Publications Policy Connecticut Law.
Journal, Law Revision Commission Administrative Law Study, Chief Justice's Task Force Gender, Justice and Courts, Governor's Task Force Federal Revenue Enhancements. Member executive committee Judicial Department. Member panel arbitrators American Arbitration Association, 1994.
General counsel National Multi Housing Council. Lecturer in field.
Board visitors Indiana University, Bloomington, 1974-1992. Member Governor's Missing Children Committee, Hartford, Connecticut Child Support Guidelines Committee, Governor's Task Force on Justice for Abused Children, Hartford, 1988-1990. Member Mayor's City of New Haven Task Force Reorganization Corporation Counsel' General’ s Office, Governor's Child Support Commission, Mayor of New Haven's Blue Ribbon Commission.
Former board directors New Haven Neighborhood Music School. Board directors, member youth advisory committee Governor's Partnership Prevent Substance Abuse Workforce-Drugs Don't Work. Member Blue Ribbon Committee Army War College, 2006.
Member American Bar Association, Connecticut Bar Association (chair committee on gender bias, Citation of Merit women and law section 1989), National Association Attorneys General (chair charitable trusts and solicitation 1988-1990), New Haven Neighborhood Music School (board directors), American Arbitration Association (arbitration panel 1994), Indiana Bar Association, Connecticut Bar Association (chair committee gender bias legal profession), Indianapolis Bar Association, Indiana Civil Liberties Union (board directors, member executive committee, chair long range planning committee, member women's rights project, membership vice president, Distinguished Service award), Connecticut Consortium Law and Citizenship Education, Inc. (board directors), Connecticut Judges Association (member legislation committee), Indiana University Law School Alumni Association (board directors), Enomene Honorary Society, Pleiades Honorary Society, Mortar Board (national fellow), Alpha Lambda Delta.
Married Mark Alan Riddle, August 15, 1971. Children: Carl Nardi, Julia Nardi.