Gore also began to work the night shift for The Tennessean as an investigative reporter in 1971. His investigations of corruption among members of Nashville's Metro Council resulted in the arrest and prosecution of two councilmen for separate offenses.

He took a leave of absence from The Tennessean to attend Vanderbilt University Law School in 1974. His decision to become an attorney was a partial result of his time as a journalist, as he realized that while he could expose corruption, he could not change it. Gore did not complete law school, deciding abruptly in 1976 to run for a seat in the U.S. House of Representatives" when he found out that his father's former seat in the House was about to be vacated.

Gore began serving in the U.S. Congress at the age of 28 and stayed there for the next 17 years, serving in both the House (1976–1984) and the Senate (1984–1993). Gore spent many weekends in Tennessee, working with his constituents.

At the end of February 1976, U.S. Representative Joe L. Evins unexpectedly announced his retirement from Congress, making the Tennessee's 4th congressional district seat to which he had succeeded Albert Gore, Sr. in 1953 open. Within hours after Tennessean publisher John Seigenthaler, Sr., called him to tell him the announcement was forthcoming, Gore decided to quit law school and run for the House of Representatives:

Gore won a seat in Congress in 1976 "with 32 percent of the vote, three percentage points more than his nearest rival." He won the next three elections in 1978, 1980, and 1982 where "he was unopposed twice and won 79 percent of the vote the other time." In 1984, Gore successfully ran for a seat in the U.S. Senate, which had been vacated by Republican Senate Majority Leader Howard Baker. He was "unopposed in the Democratic Senatorial primary and won the general election going away," despite the fact that Republican President Ronald Reagan swept Tennessee in his reelection campaign the same year.

During his time in Congress, Gore was considered a "moderate" (he referred to himself as a "raging moderate") opposing federal funding of abortion, voting in favor of a bill which supported a moment in silence in schools, and voting against a ban on interstate sales of guns. His position as a moderate (and on policies related to that label) shifted later in life after he became Vice President and ran for president in 2000.

During his time in the House, Gore sat on the Energy and Commerce and the Science and Technology committees, chairing the latter for four years. He also sat on the House Intelligence Committee and in 1982 introduced the Gore Plan for arms control, to "reduce chances of a nuclear first strike by cutting multiple warheads and deploying single-warhead mobile launchers." While in the Senate, he sat on the Homeland Security and Governmental Affairs, the Rules and Administration, and the Armed Services Committees. In 1991, Gore was one of ten democrats who supported the Gulf War.

Gore was one of the Atari Democrats who were given this name due to their "passion for technological issues, from biomedical research and genetic engineering to the environmental impact of the "greenhouse effect." On March 19, 1979 he became the first member of Congress to appear on C-SPAN. During this time, Gore co-chaired the Congressional Clearinghouse on the Future with Newt Gingrich. In addition, he has been described as having been a "genuine nerd, with a geek reputation running back to his days as a futurist Atari Democrat in the House. Before computers were comprehensible, let alone sexy, the poker-faced Gore struggled to explain artificial intelligence and fiber-optic networks to sleepy colleagues." Internet pioneers Vint Cerf and Bob Kahn noted that, "as far back as the 1970s, Congressman Gore promoted the idea of high speed telecommunications as an engine for both economic growth and the improvement of our educational system. He was the first elected official to grasp the potential of computer communications to have a broader impact than just improving the conduct of science and scholarship [...] the Internet, as we know it today, was not deployed until 1983. When the Internet was still in the early stages of its deployment, Congressman Gore provided intellectual leadership by helping create the vision of the potential benefits of high speed computing and communication. As an example, he sponsored hearings on how advanced technologies might be put to use in areas like coordinating the response of government agencies to natural disasters and other crises."

As a Senator, Gore began to craft the High Performance Computing and Communication Act of 1991 (commonly referred to as "The Gore Bill") after hearing the 1988 report Toward a National Research Network submitted to Congress by a group chaired by UCLA professor of computer science, Leonard Kleinrock, one of the central creators of the ARPANET (the ARPANET, first deployed by Kleinrock and others in 1969, is the predecessor of the Internet). The bill was passed on December 9, 1991 and led to the National Information Infrastructure (NII) which Gore referred to as the "information superhighway."