In nearly three decades atop patent litigation, Matthew Powers collected all the trappings of Big Law success: Nine-figure victories. Stately homes. A top Chambers ranking. Three ex-wives.

There was little left to accomplish — and then fearsome patent litigator John Desmarais left Kirkland & Ellis in 2009 to found his own firm, armed with a vast collection of patents from Micron Technology and a bold plan for monetizing them. His move showed that by crossing over to plaintiffs work, a seasoned defense lawyer could get some skin in the game and nab a fortune unattainable in Big Law. Powers, who friends and former colleagues say is driven to be at the top of his profession, set out to do that two years ago, though he says he'd been considering such a move since long before Desmarais made the jump.