He was born in Millen, Georgia, educated at Mercer University in Macon, Georgia and served in the United States Army. He later worked as a lawyer, assistant district attorney, judge and member of the Georgia Senate from 1981-93, serving as president pro tem in his last term.

Deal served his first congressional term and the first four months of his second term as a Democrat. However, he switched to the Republicans in April 1995 after stating he felt uncomfortable being the most conservative Democrat in the Georgia delegation. He won his first full term as a Republican in 1996 by a large margin even though his Democratic opponent, McCracken Poston, was endorsed by Deal's predeccessor, popular eight-term Democrat Ed Jenkins. It was the first time his district had elected a Republican since Reconstruction. He was reelected unopposed from 1998 to 2004, but will face a Democratic opponent in 2006. Two Democrats are running for the nomination. Deal is still heavily favored for an eighth term, especially since a mid-decade redistricting made the 10th even more Republican.

Deal's voting record had been relatively moderate in his first term, but veered sharply to the right after his party switch. Originally pro-choice on abortion, he altered his stance to pro-life. His final conversion to conservative Republicanism occurred in 1998, when he voted for all four articles of impeachment against Bill Clinton.

With Deal's party switch, no white Democrats represented Georgia in the House until the election of Jim Marshall in 2002.

As an immigration reform advocate he has introduced such reform legislation as H.R. 698, the Citizenship Reform Act which would eliminate birthright citizenship in the U.S.