Carter attended First Baptist Church in Washington D.C. while he was President.
Carter is considered by most historians to be the first formally Evangelical/self-declared Born Again president. Carter was long associated with the Southern Baptist Convention, and was a Southern Baptist while in office. Although he remained a devout Baptist, he renounced his association with the Southern Baptist Convention in October 2000.
Carter was formerly a Southern Baptist, although during his presidential campaign said his favorite Christian theologians were not Baptist. Carter has had some disagreements with the leadership of the Southern Baptist Convention, including statements he made in 1997 in response to SBC attacks on Mormons. In a teleconference interview with religion writers from throughout the United States, Carter said Mormons are already Christian and he criticized the SBC for trying to proselyte Mormons. He stated: "Too many leaders now, I think, in the Southern Baptist Convention and in other conventions, are trying to act as the Pharisees did, who were condemned by Christ, in trying to define who can and who cannot be considered an acceptable person in the eyes of God. In other words, they're making judgments on behalf of God. I think that's wrong." Carter said that "the people in my own local church have no interest in trying to condemn Mormons or trying to convert Mormons to be good old Baptists like me." [Source: David W. Cloud, Fundamental Baptist Information Service, 16 November 1997, 1701 Harns Rd., Oak Harbor, WA 98277; Carrie Moore, "Are Mormons Christians," Deseret News, Nov. 15, 1997].
In October 2000, Carter again made headlines with his widely-publicized decision to leave the Southern Baptist Convention. Carter sent out over 75,000 letters to Southern Baptist churches nationwide explaining his decision. He felt that his Christian commitment had not changed, but that the cumulative changes in the SBC had made the organization a group that his Christian conscience could not let him support. [More about Carter and the SBC.]
From: Richard N. Ostling (Associated Press), "Old custom: U.S. presidents tangle with their religious denominations", published 9 February 2003, in The Post & Courier (Charleston, South Carolina) (http://charleston.net/stories/020903/rel_09prez.shtml; 6 July 2003 version of page viewed via archive.org on 29 November 2005):
..."It's relatively easy for presidents to get on the outs with their denominations," says Wake Forest University Divinity School Dean Bill J. Leonard. It's hard to find a 20th-century president who didn't butt heads with some in his faith:
...Harry Truman, the first Southern Baptist in the White House, annoyed some in that denomination by spouting "hells" and "damns" in conversation. Jimmy Carter angered Baptist pastors by favoring abortion rights.
...Ultimately, Southern Methodist University ethicist Robin Lovin says, politicians' moral judgments are influenced far less by today's church pronouncements than by their religious upbringing. The sermons, discussions and Sunday school classes in their home congregations many years ago may be their guide.