Williams worked with Alabama Republican Party chair Marty Connors to establish the Southern Republican Exchange think tank. He also chaired the Greater Birmingham Young Republicans and worked as director of the Alabama House Republican Caucus from 1990 to 1995.
Williams served as Jefferson County Tax Collector from 1995 to 2003, and served as president of the National Republican County Officials. In 2005, Williams founded Jack Williams Associates which provided public relations, government relations and political consulting services.
Williams was first elected to the Alabama House when he beat Tom Buck in the 2006 Republican primary and went unopposed in the general election. While serving in the legislature, he chaired the Alabama House Commerce and Small Business Committee. In 2010 he and Democratic colleague Merika Coleman co-sponsored the Williams-Coleman Human Trafficking Act, giving state and local law enforcement agencies more scope to investigate and prosecute human trafficking crimes.
In 2010 Williams ran unopposed in the Republican primary and defeated independent challenger Chip McCallum III in the general election. Williams defeated Republican challenger David Wheeler in the 2014 Republican primary and Democrat Salvatore Bambinelli in the 2014 general election. Later that year, he was honored as "Legislator of the Year" by the American Legislative Exchange Council. In 2015 Williams filed a bill that would have re-structured the University of Alabama Board of Trustees to increase representation for the system's Huntsville and Birmingham campuses. That legislation did not make it out of committee.
Williams announced in early 2017 that he would not run for a fourth term.
Outside of politics, Williams has served as board chair for Greater Birmingham Habitat for Humanity and worked as director of development for Aldridge Gardens in Hoover from 2011 to 2013. From 2004 to 2015 he published BlazerSportsReport.com, an online affiliate of Rivals.com which covers UAB Blazers athletics. He and his wife, Glenda have two children: Regan and Jordan. He attends the Fullness Christian Fellowship.
- Birdsong, Nick (November 25, 2014) "State Rep. Jack Williams lays out plan to restructure University of Alabama BOT system, benefit UAB football." The Birmingham News
- Britt, Bill (September 20, 2015) "Breaking Investigative Report: More Potential Problems for Rep. Jack Williams." Alabama Political Reporter