Sundquist was born in Moline, Illinois and attended Augustana College in that city. In his early career, he sold class rings for Jostens. Moving to Memphis, Tennessee, he became very active in the Republican Party.

He first attracted political attention when he became chairman of the Shelby County Republican Party. When 6th District Congressman Robin Beard ran for the Senate against incumbent Jim Sasser in 1982, Sundquist ran for the Republican nomination to succeed Beard in the district, which had been renumbered the 7th in redistricting. He succeeded in winning the nomination in August, 1982, and then defeated Democrat Bob Clement, son of former governor Frank G. Clement, in the November, 1982 general election by seven points. It was the first (and as of 2006, only) time a Democrat had come within 10 points in the 7th District since it fell into Republican hands in 1972. (Clement later won election to the Nashville-based 5th District in a 1988 special election and served there until 2003). He was unopposed for reelection in 1984 and was reelected four more times by landslide margins in what had become a solidly Republican district.

Sundquist established a very conservative voting record in Congress, and was a darling of conservative-oriented groups such as the National Federation of Independent Businesses and the American Conservative Union. He was regarded as a rising star by the Tennessee Republican Party. When popular Democratic governor Ned McWherter was prevented from seeking a third term in 1994 by term limits, Sundquist seemed like the logical choice for the GOP nomination and easily won it in August 1994. He faced Phil Bredesen, the Democratic mayor of Nashville in November, and won by almost 10 points. The margin surprised many pundits who expected this to be one of the more competitive races of the 1994 cycle. It was a big night for Tennessee Republicans, who also captured both Senate seats. They also won a majority of the state's congressional delegation for only the second time since Reconstruction.

Sundquist's first term was rather unremarkable, although state government grew quite rapidly in comparison to the growth of the state's economy as a whole. He attracted no serious opposition within his party for renomination in 1998. His Democratic opponent, Nashville attorney and entrepreneur John Jay Hooker, was regarded at this stage in his career as a perennial candidate and gadfly rather than a serious contender, and Sundquist won reelection with almost 69f the vote.

Immediately upon his reinauguration, Sundquist set out to raise more revenue for the state. which had traditionally been one of the lowest-tax jurisdictions in the country. His tax reform plan included a state income tax, previously regarded as political suicide in Tennessee. He quickly offended most of his grassroots base, and his popularity plummeted. Only certain elements in the business community supported him from the Republican Party, and many Tennessee Democrats, especially conservative rural ones, had no interest in either alienating their constituents or helping a Republican. The income tax issue dominated Sundquist's second term, but was never passed. Sundquist became very isolated politically, with many of his Democratic supporters doing so only because they wished to see the income tax implemented in a way in which the Republicans could be blamed for it. Several of his original conservative supporters, such as State Senator Marsha Blackburn, led street demonstrations against him. Many leading figures in his own party publicly disavowed him.

Sundquist, like McWherter before him, was barred from running for a third term in 2002 by the state constitution. Unlike McWherter, however, he was so unpopular at the end of his term that it is highly unlikely he would have even won the Republican nomination, let alone reelection, had it been possible for him to run again. His support of Congressman Van Hilleary's candidacy is considered a major factor in Hilleary's loss to Bredesen in 2002.

In retirement, rumor and innuendo have continued to swirl about him, which became more intense with the conviction of a former mid-level member of his administration in May, 2004 for illegally routing a "no-bid" contract for job training for the unemployed to a close personal friend of his. On November 4, 2004, another friend of his was indicted, charged with false statements allegedly made in conjunction with another no-bid contract, this one to connect Tennessee schools to the Internet amounting to nearly $200,000,000, and with destroying e-mails and other records pertinent to the case. In the spring of 2005, this friend was sentenced to prison for having fraudulently received a state contract by utilizing his close relationship with Sundquist. In July 2005 a federal judge said Sundquist was the "impetus" for the investigation, although he was not yet charged with any crime.

In August, 2004, Sundquist "crashed" the Republican National Convention in New York City, appearing uninvited. (Rumors that an effort was going to be made to include him in the official state delegation had apparently been unfounded.) However, due to his former importance in the state and the considerable embarrassment that it would have entailed to have him removed, he was made welcome by certain members of the Tennessee delegation, many of whom had been close friends in the past.

In July 2005 Sundquist was named head of a national panel on improving Medicaid.

Preceded by: Ed Jones United States Representative for the 7th District of Tennessee 1983-1995 Succeeded by: Ed Bryant Preceded by: Ned McWherter Governor of Tennessee 1995-2003 Succeeded by: Phil Bredesen