From the year 1987 to 2012, Williams represented Senate District 16, a position he secured upon the retirement of fellow Republican Doug Moseley.

[2] Because of his father's office, David Williams met several politicians over the years, including Republicans, Senator John Sherman Cooper and Representative Tim Lee Carter.

[10] His most notable actions were in opposition to an education reform package proposed by Governor Martha Layne Collins, a Democrat, during a special legislative session in July 1985.

[15] The seat, representing the 16th district (Adair, Casey, Cumberland, Green, Metcalfe, Russell and Taylor counties), was left open by the retirement of incumbent legislator Doug Moseley of Campbellsville.

[18] In 1987, Williams was named the state organizational chairman for Vice-President George H. W. Bush's presidential campaign, and he was a delegate to the 1988 Republican National Convention.

[10] In December 1988, Governor Wallace Wilkinson, a Democrat, called a special legislative session to consider the creation of a state lottery.

Williams proposed an amendment, which did not pass, to allow counties to decide whether or not to sell lottery tickets, similar to the state's existing local option liquor laws.

[30] During the 1992 legislative session, Williams and fellow Republican Gene Huff walked out of the Senate chambers just before a vote on a prevailing wage bill.

"[34] A Franklin County circuit court judge ruled that the committee system was not unconstitutional and further, that lawmakers could not be sued for actions taken in their capacity as legislators because of the state constitution's doctrine of separation of powers.

[41] Thompson did question Williams' conservative credentials on grounds that he voted in favor of the tax increase associated with the Kentucky Education Reform Act.

[41] Ormerod's campaign largely focused on socially conservative issues, but it was Williams who secured the endorsement of Kentucky Right to Life, who cited his lawsuit to free the three abortion bills from committee in the 1992 legislative session.

[43] Given his limited finances, Williams relied on news conferences and interviews on small town radio stations to get his message out.

[44] During the campaign, Williams attempted to paint Ford as too liberal for Kentucky voters, citing his votes against the Gulf War and Clarence Thomas' confirmation to the U.S. Supreme Court.

[43] After his loss in November 1992, Williams declared his candidacy for Commonwealth's Attorney for the 29th district (Adair, Cumberland, Casey, and Monroe counties).

[5][46] Williams cited his late start in campaigning due to a special legislative session called by Governor Brereton Jones as the main factor in his defeat.

[59] In early 1999, weakened by the attempt to remove him as floor leader, Dan Kelly did not seek the post again at the General Assembly's organizational meeting.

[62] Saunders pledged to resist the Republicans' ouster, claiming the state constitution called for the election of the Senate President to a two-year, uninterrupted term during the Assembly's odd-year organizational sessions and made no provision for unseating him in the interim.

[62] After requesting an advisory opinion on the issue from Attorney General Ben Chandler and threatening to take the case to the Kentucky Supreme Court, Saunders backed down in October 1999, announcing he would resign rather than wage a protracted legal battle.

[63] The move left Williams, the longest-serving Republican in the Senate and the third-longest serving members in the entire chamber, as Sauders' presumptive replacement.

[64] Martin won the Republican nomination after most of the party's potential high-profile candidates chose not to run, citing concerns that the state's campaign finance laws would make challenging an incumbent difficult.

[66] The transition was generally regarded as cordial and smooth, although Democratic minority leader David Karem asked that the Senate journal reflect that the shift in majority was due to party defection, not a vote of the people.

[66] Democrats were also upset that Williams removed a minority seat from the powerful rules committee, giving the majority party a 5–3 advantage in representation.

[67] Senate Republicans remained firmly against enacting any new taxes for most of the session, hampering the General Assembly's ability to pass a bundled budget.

[68] During the session, Williams also forcefully criticized Patton for trying to reverse elements of a workers' compensation reform package Patton had passed during his first term and opposed a Democrat-backed plan for distributing federal money from the Tobacco Master Settlement Agreement to county governments instead of allowing the state government to allocate it toward a centralized plan for reducing the state's dependence on tobacco.

[75] Late in the session, Williams introduced a proposal to the bipartisan Legislative Research Commission – which was made up of eight Democrats and eight Republicans – that would have allowed each chamber to name their own members to the joint interim committees, helping to resolve the parity issue.

[74] In July 2001, Williams and House Speaker Jody Richards reached an agreement to allow committees of four representatives and three senators to meet up to three times in advance of the 2002 legislative session.

[77] Republicans charged that Patton was intentionally delaying the redistricting so that the 2002 legislative elections would take place with districts drawn by the Democrat-controlled General Assembly a decade earlier to favor Democratic candidates.

[77] In September 2001, a group of Democratic senators claimed that the official census figures underrepresented the state's population by approximately 50,000 people, especially minorities, children, and the homeless.

He ran unsuccessfully against Democratic governor Steve Beshear on a ticket with lieutenant-governor nominee, state Agriculture Commissioner and former Kentucky Wildcats men's basketball standout Richie Farmer.

Late in 2012, a seat on the Kentucky 40th Circuit Court, which includes Cumberland County, opened up when Eddie Lovelace died from a fungal infection apparently caused by tainted steroid injections.