Donald Wayne Riegle Jr. (born February 4, 1938) is an American politician, author, and businessman from Michigan. He served for five terms as a Representative and for three terms as a Senator in the U.S. Congress.

He attended Flint Junior College (now Mott Community College) and Western Michigan University, graduated with a B.A in business administration and economics from the University of Michigan-Flint in 1960, and received an M.B.A. in finance from Michigan State University in 1961.^[1]

In 1966, Richard Nixon persuaded Riegle to return to Michigan to run for Congress.^[2] Riegle was then 28 years old and considered to be a moderate Republican. Nixon attended an early campaign fundraiser, and talked up Riegle's prospects to reporters.^[2]

Riegle defeated incumbent Democratic U.S. Representative John C. Mackie, to be elected from Michigan's 7th congressional district to the 90th Congress. Mackie was one of the Michigan Five Fluke Freshmen who lost their seats after a single term.^[2]

In his first action as Chairman of the Senate Banking Committee, Riegle led the efforts to reform the savings and loan industry, which resulted in the Financial Institutions Recovery, Reform, and Enforcement Act of 1989 ("FIRREA").^[3]

Riegle endorsed Bernie Sanders for the Democratic nomination for President of the United States^[4] in both 2016 and 2020.^[5]

• List of American politicians who switched parties in office
• List of United States representatives who switched parties