WASHINGTON — On the eve of a critical Congressional vote last week on a sweeping measure to regulate Wall Street, the prominent lobbyist Tony Podesta met with one of the lawmakers to go over some final language and discuss the effect it could have on his many corporate clients.

Once that was over, Mr. Podesta pivoted back to another client, BP, to help the company navigate Congressional waters and, in short, try to prevent an ugly situation from getting even uglier.

For weeks now, the two biggest issues in Congress have been cleaning up Wall Street and cleaning up the Gulf Coast. To the surprise of no one in the capital’s K Street corridor, Mr. Podesta — Democratic fund-raiser, avid art collector and member of a family brand in Washington — has had a big hand in both. And medical companies have also been drawn to his firm, particularly in the wake of the health care legislation.

In a remarkable season of lobbying, business is booming for the Podesta Group, already one of Washington’s biggest players. It has become particularly lucrative for firms like Mr. Podesta’s that are skilled at wielding influence in Congress, the center of epic debates on health care, bailouts and financial regulations.