Ann M. Williams received her undergraduate degree from University of Iowa in 1992, where she majored in journalism and political science.  She graduated from Drake University Law School in Des Moines, Iowa, in 1994. While in law school, Ms. Williams clerked for the Legal Assistance Foundation of Chicago and was among the first recipients of the Public Interest Scholarship at Drake.  In 1995 Ms. Williams was admitted to practice law in Illinois and worked as a staff attorney for the Illinois Speaker of the House.  She also served as a Law Clerk for Appellate Court Justice Margaret O’Mara Frossard in the First District, Chicago, Illinois, before joining Storino, Ramello & Durkin in 1999.

When Lisa Madigan was elected as Attorney General of Illinois, Ms. Williams left the firm to join the Attorney General’s team as Legislative Director and served in this role for several years. In this capacity, Ms. Williams was charged with advancing the Attorney General’s legislative agenda before the Illinois General Assembly and was responsible for helping to craft and implement key parts of the Attorney General's public interest agenda. Ms. Williams left the Attorney General’s office in 2007 to join the Government Affairs team for Wyeth Pharmaceuticals.   

In the fall of 2009, Ms. Williams left the private sector to become a candidate for Illinois State Representative in the 11th District on Chicago's north side. The district includes the Chicago neighborhoods of West Lakeview, Roscoe Village and North Center, as well as parts of Lincoln Park and Lincoln Square.  She won the November 2, 2010, election, with over 70% of the vote and became State Representative for the 11th District. In March 2011, Ms. Williams ran unopposed in the Democratic primary and was unopposed in the general election, which took place on November 6, 2012. She won re-election in the 2012 election for Illinois House of Representatives District 11.

Ms. Williams returned to Storino, Ramello & Durkin in 2010 where she practices municipal law.