As chair of the Senate Banking Committee, he pushed financial reforms of the savings and loan industry and, in 1991, helped secure treatment for Gulf War syndrome for Persian Gulf veterans.

Family statements portrayed him as a caring leader who fought for justice and economic opportunity, with memorial arrangements pending.

Riegle began his political career as a Republican before switching to the Democratic Party, later earning a reputation as a diligent, justice-driven leader who fought for working people.

Among his notable legislative acts, he led opposition to NAFTA and supported the Equal Credit Opportunity Act of 1973, which barred gender or marital-status discrimination in credit applications.

He opposed NAFTA, arguing it would affect Michigan jobs, and championed economic development and expanded health insurance access for residents.

After leaving office, he served as chairman of government relations for APCO Worldwide starting in 2001, continuing involvement in public affairs.

Over his career, Riegle balanced industry interests with labor concerns, evolving from a Vietnam War dove to a pragmatic senator known for securing constituent benefits.

His educational path included Central High School in Flint, an undergraduate degree from the University of Michigan (Flint campus) in 1960, an MBA from Michigan State University in 1961, and graduate studies at Harvard (completed without a thesis).

Riegle was involved in the Keating Five controversy in 1990; while the Ethics Committee found no legal or Senate rule violations, it said his conduct raised questions of impropriety and an appearance of influence peddling.

Longtime Michigan politician Donald W. Riegle, who served in the U.S. House (1967–1975) and the U.S. Senate (1976–1994), died at age 88 in San Diego after a cardiac arrest, with his wife Lori Hansen Riegle by his side.

His long tenure reflected influence across multiple administrations, marking him as a significant figure in Michigan and national politics.

A historical photo from 1980 captures Riegle with President Jimmy Carter and other Michigan officials at a Volkswagen plant signing event.