Manhattan-based solo practitioner Maurice Pianko has a beef with companies that hire unpaid interns, and he hasn't been shy about it. He insists he's more interested in labor reform than generating litigation paydays, warning that even small-time employers should be worried. But that didn't stop Pianko from going after a big new target on Monday.

Along with co-counsel at Virginia & Ambinder, Pianko brought a putative class action against Warner Music Group Corp. in New York Supreme Court, seeking to recover hourly wages and overtime pay for more than 100 of the record label's former interns. The complaint—the first of its kind aimed at the music industry—alleges violations of New York labor laws on behalf of interns supposedly tasked with "answering telephones, making photocopies, making deliveries, preparing coffee, getting lunch for paid employees, and other similar duties."

In an interview, Pianko said that the lawsuit is the tenth of its kind nationwide, and the fourth that he's been directly involved in. He attracts clients through his Web site, Intern Justice. And he hunts for defendants partly by scanning job postings on Craigslist. "I'll see dozens upon dozens of postings advertising positions that are identical to paid positions, except at the end it'll say 'this is an unpaid internship.'" he told us.

Pianko currently shares the niche with the much larger plaintiffs-side firm Outten & Golden, which on June 11 won a groundbreaking ruling certifying a class of former interns at Fox Searchlight Pictures, and which two days later brought a similar case against the magazine publisher Condé Nast. Outten is also fighting to revive a parallel case it brought on behalf of unpaid Hearst Corporation interns.

Two of Pianko's cases seek class action status, and his targets have been diverse. He's helped sue fashion designers (see here and here), as well as the Portela Law Firm in Manhattan. Some of his cases were brought in federal court, alleging violations of the Fair Labor Standards Act, while others, like Monday's Warner Music suit, are premised on state law. Pianko says he likes filing federal cases, because they have a greater precedential impact, but that New York labor law is friendlier to plaintiffs, partly because of a lengthy statute of limitations.

"The idea behind Intern Justice was not to cherry pick lucrative cases and try to make a windfall," Pianko said. "Mega-sized corporations are where the money is for class actions lawyers, but I don't want them to be only ones being held accountable."

We wondered if Pianko, a 2009 graduate of Fordham Law School, soured on unpaid internships based on personal experience. He says he did a perfectly legal unpaid internship with a judge during law school, and relished the opportunity. He has, however, sued a law firm he worked for right after law school, alleging they bilked him out of wages. The lawsuit has been a "painful" experience, he said, and gave him a newfound appreciation for "the plight of unpaid interns, who do real work and are told it's not worth anything."