Dunkin previously served as a Democratic member of the Illinois House of Representatives, representing the 5th District from December 2002 until January 2017 and as an appointed by Governor Bruce Rauner to fill a vacancy on the Board of Commissioners for the Metropolitan Water Reclamation District of Greater Chicago in May 2018,[2] serving until December of that same year.

Most recently, he was the Director of the Robert Taylor Boys and Girls Club of Chicago, where he managed over $2.5 million in program services.

Dunkin is currently a member of the Attorney Registration Disciplinary Commission (appointed by Illinois Supreme Court), Board of the Chicago International Film Festival, Lawson YMCA, Near North Health Services Corp, Phi Beta Sigma fraternity and the Governor's Film Task Force.

As a member of the Illinois House of Representatives, Dunkin served on seven committees: International Trade & Commerce, Financial Institutions, Insurance, Mass Transit, Appropriations-High Education, Telecommunications, and Chairman of Tourism and Conventions.

Its implementation would have impeded the Governor's ability to force a "lock-out" of state workers during contract negotiations and also prevented the union from striking.

"[10] On November 10, 2015, Representative Dunkin once again sided with Governor Rauner rather than his Democratic caucus involving a vote on child care assistance.

[…] "Let me be clear that no one bears more responsibility today for the defeat of this legislation, which protects our children and child care and home care in Illinois than Rep. Ken Dunkin himself," Jaquie Algee, vice president of SEIU Healthcare Illinois said at a press conference organized by House Speaker Michael Madigan.

– At one point during an intense, emotional floor debate, state Rep. Jaime Andrade stripped Dunkin's nameplate from the front of his seat, walked it over to the Republican side of the chamber then threw it down, saying: "He's all yours now.

"[11][12] The Illinois AFL-CIO Executive Board voted on December 17, 2015 to endorse Juliana Stratton for State Representative in the Democratic Primary Election for the 5th District.

[15][16] On March 7, 2016, Representative Dunkin's opponent, attorney Juliana Stratton, announced that the President of the United States had personally endorsed her in the upcoming primary.

When President Obama was addressing the Illinois General Assembly, the POTUS said reaching political compromise across the aisle "doesn't make me a sellout to my own party."

Pat Dowell (3rd) appeared at a South Side press conference to accuse Rep. Ken Dunkin of buying early votes in the battle to keep his 5th District seat in the state House of Representatives.

[20] On March 15, 2016, Democratic challenger Juliana Stratton defeated Ken Dunkin in a decisive manner, as reported by WGN News.