Over the last three decades, corporate white-collar criminal defense and investigations practices have become established within the nation’s largest law firms. It was not always this way. White-collar work was not considered a legal specialty. And, historically, lawyers in the leading civil firms avoided criminal matters. But several developments occurred at once: firms grew dramatically, the norms within the firms changed, and new federal crimes and prosecution policies created enormous business opportunities for the large firms. Using a unique data set, this Article profiles the Big Law partners now in the white-collar practice area, most of whom are male former federal prosecutors. With additional data and a case study, the Article explores the movement of partners from government and from other firms, the profitability of corporate white-collar work, and the prosecution policies that facilitate and are in turn affected by the growth of this lucrative practice within Big Law. These developments have important implications for the prosecution function, the wider criminal defense bar, the law firms, and women in public and private white-collar practices.