Charles Colson, a ruthless White House aide during the Watergate era, died on Saturday.
Colson, 80, who compiled an "enemies list" for President Richard Nixon, died of complications from a brain hemorrhage.
The Prison Fellowship Ministries said he was admitted to a hospital in Fairfax, Virginia, on 31 March.
He underwent surgery to remove clotting on his brain, but his condition deteriorated earlier this week.
Colson served as counsel to the president from 1969 - 1973 and a major part of his job was playing hardball politics to assure Nixon's re-election in 1972.
"I would walk over my own grandmother if necessary" to get Nixon re-elected, he once said.
Colson and other aides at the White House engaged in a series of illegal acts that resulted in Nixon resigning the presidency in 1974 in the face of impeachment over the Watergate scandal.
Watergate grew out of a break-in at the Democratic National Committee headquarters at the Watergate office complex in Washington in 1972.
Colson ended up with a sentence of one to three years in prison due to a break-in at the offices of the psychiatrist to Daniel Ellsberg, the man who leaked the Pentagon Papers to The New York Times.
While under investigation, Colson became an evangelical Christian. After serving seven months at Maxwell Correctional Facility in Alabama, he founded the Prison Fellowship to push prison reform and provide religious opportunities for prisoners.
For the rest of his life, Colson worked to bring Christian messages and Bible study to prisoners and their families. In 1983, he helped found Justice Fellowship to rehabilitate prisoners and bring about prison reform such as better job training for inmates.
Time magazine named Colson one of the 25 most influential evangelical Christians in America in 2005.