When he’s in Chicago, Michael Zalewski is a lawyer at the downtown offices of Taft Stettinius & Hollister LLP.

At the same time, in Springfield, the Democratic state representative from Chicago’s Southwest Side has taken the lead role in the effort to legalize betting on sports in Illinois.

And it’s in Springfield where the Taft law firm has dozens of lobbying clients with interests in gambling, including sports betting.

The situation prompted complaints from a rival gambling company, Zalewski said. And in response to that, he said, he has removed himself as the lead negotiator in talks to forge a bill that could bring tens of millions of dollars of new revenue to the cash-strapped state government.

“In the last week there’s been a concentrated effort by certain stakeholders to accuse me of being the problem when it comes to passing the sports-betting law,” Zalewski told WBEZ on Wednesday.

Although it’s not wrong or even at all unusual for state lawmakers to have other jobs, Zalewski’s increasingly prominent role in the Illinois House came as clients of his own employer pushed for potentially lucrative changes in the laws.

A WBEZ review of state lobbyist-disclosure documents shows Taft is working to influence state government actions regarding gambling on behalf of more than 30 clients.

The long list of Taft lobbying clients with state-government interests includes Penn National Gaming Inc., a Pennsylvania-based operator of casinos and racetracks, including the casinos in Aurora, Joliet and Alton, Ill.

Springfield sources say the complaints about Zalewski’s side job at Taft came from executives of the company that owns Rivers Casino in Des Plaines. A spokeswoman for Rivers Casino declined to comment.

Last week, Zalewski’s office circulated a draft sports-betting law. But he says he withdrew from the negotiation soon after that.

The dispute arose in the final days of a legislative session that ends Friday. A huge array of gambling interests are constantly jostling to influence how Springfield regulates and taxes casinos, horse-racing tracks, video-gambling parlors and other state-sanctioned gambling venues.

And questions about conflicts of interest are nothing new to the debate. On Tuesday, WBEZ and ProPublica Illinois revealed that some Illinois lawmakers have ties to video-gambling companies , which have done a booming business in the state since the machines were legalized a decade ago.

Zalewski, whose father was a Chicago alderman, has been a state lawmaker since 2008 and is the chairman of the Revenue & Finance Committee of the Illinois House.

According to his bio on Taft’s website, Zalewski also is “of counsel” to the firm. That means he is employed by the firm but is not a partner with an equity stake in the firm. He said he does not work for any of the firm’s many clients who have interests in Springfield.

At the state Capitol, Zalewski long has championed sports betting, and he estimates that it would bring between $40 million and $80 million a year to the state’s coffers.

After the U.S. Supreme Court cleared the way for sports betting, Zaleswki said he made sure that there were no legal or ethical hurdles to his acting as the chairman at hearings on crafting a sports-gambling law for Illinois.

“I asked and received an ethical opinion from my chief ethics officer,” Zalewski said. “I’ve complied with all ethical and legal guidelines regarding this topic, and I’ve acted with integrity and honor.”

Still, he said another lawmaker, Democrat Robert Rita from Blue Island, has replaced him in the negotiations on sports betting.

“I said earlier this week, if you think I’m the problem, then I’ll take a step back,” Zalewski said. “I’ve turned it over to our gaming negotiator Bob Rita to try to bring agreement among all the stakeholders.

“It isn’t because I perceive a conflict. It’s simply because I don’t want to stand in the way of progress on a critical issue. I’ve honored that commitment.”