Boyd Johnson III, a former No. 2 at the U.S. attorney's office in Manhattan, has left his role as co-chairman of investigations and criminal litigation at Wilmer Cutler Pickering Hale and Dorr in order to become general counsel at Soros Fund Management LLC, a private investment firm controlled by billionaire businessman and philanthropist George Soros.

Johnson officially starts at the investment management firm on May 1. He follows a well-worn path of former top federal prosecutors heading to prominent in-house roles at hedge funds.

Kevin O'Connor, a former top U.S. attorney in Connecticut, became general counsel of Steven Cohen's Point72 Asset Management LP in 2015. Earlier that year, Jenna Dabbs, a former narcotics chief in the Southern District of New York, joined William Ackman's Pershing Square Capital Management LP as senior counsel at a member of the investment team. Richard Zabel, who succeeded Johnson as deputy U.S. attorney in Manhattan, also headed to a general counsel role in early 2015 at Paul Singer's Elliott Management Corp.

Johnson, who joined Wilmer's New York office in 2011, spent two years as deputy U.S. attorney in the Southern District of New York, where he previously served as chief of the office's public corruption unit and head of its international narcotics trafficking unit. Johnson began his legal career almost three decades ago with a federal judicial clerkship in California followed by time working as an associate at Gibson, Dunn & Crutcher in New York.

In 1999, he left private practice to join the U.S. attorney's office in Manhattan, where he would spent the next 12 years. During his time in the SDNY, Johnson led several notable prosecutions and investigations. As head of the office's narcotics unit, Johnson oversaw the investigation that led to the eventual arrest and late 2008 conviction of Monzer al-Kassar, a notorious Syrian arms trafficker nicknamed the “Peacock.”

Johnson became chief of the SDNY's public corruption unit in 2006, a role that saw him oversee an investigation into a high-end prostitution ring that resulted in the resignation of former New York Gov. Eliot Spitzer. Former SDNY chief Preet Bharara then elevated Johnson to deputy U.S. attorney in 2009. The American Lawyer noted in a 2014 profile of Bharara that Johnson played a key role in bringing cases under the False Claims Act.

Johnson joined Wilmer in 2011, where he represented financial services firms, public companies and their senior executives in various criminal and civil matters. At Soros Fund Management, which its namesake founded in 1969, Johnson heads to one of the most profitable firms in the hedge fund industry.

A Soros Fund Management spokesman confirmed in a statement that Johnson will replace longtime general counsel Maryann Canfield, who is transitioning into a new role as chief operating officer of its family services division, where she will work directly on personal matters for the Soros family. Johnson was unavailable Monday to discuss his new role.