Edgar died Tuesday at his home in Burke, Va., after suffering a heart attack while running on a treadmill, said Mary Boyle, a spokeswoman for Common Cause, a lobbying group Edgar led as president.
"Our country has lost one of its most ardent, passionate and effective voices of a more open and honest democracy," Rep. Nancy Pelosi, D-Calif., said.
Edgar, born May 29, 1943, began his career as a Methodist minister and won a seat in Congress in 1974 as part of a wave of Democrats elected after the Watergate scandal.
He was elected to six terms and resigned in 1986 to run for the Senate against Republican incumbent Arlen Specter. He lost by 13 percentage points.
Edgar characterized himself as being "called to a different world vision," The New York Times reported
As a minister, he was responsible for helping start Philadelphia's first homeless shelter for women and as congressman he tried to curb public works spending, the Times said. As chief of the National Council of Churches, he urged member churches to emphasize aid to the poor. With Common Cause, he fought to stop the expansion of campaign financing.
At the time of his death, Edgar was pushing for reform of Senate rules requiring 60 votes to halt a filibuster.
Edgar is survived by his wife of 48 years, Merle Louise Deaver, three sons, eight grandchildren, his mother and two brothers.