Mayer Brown has re-hired former federal prosecutor Sean McDonnell as a partner to further expand its litigation and dispute resolution practice in Washington DC.

McDonnell was previously an assistant US attorney in the US Attorney’s Office for the Eastern District of Pennsylvania, first-chairing several jury trials and prosecuting a variety of cases involving tax fraud, wire fraud, bank fraud and public corruption. Most recently he served as the US Attorney’s coordinator for Covid-19-related government fraud cases.

Richard Spehr, leader of Mayer Brown’s global litigation and dispute resolution practice, said: “Sean is widely respected as an extremely talented trial lawyer with extensive civil litigation, government enforcement and investigations experience; we are fortunate to welcome him back to Mayer Brown.”

Spehr added: “Sean will work closely with our expanding bench of former federal prosecutors and high-ranking government officials to help clients with their most challenging bet-the-company matters.”

Prior to his stint as a federal prosecutor, McDonnell was a litigator in Mayer Brown’s Washington and Chicago offices. He also previously clerked for Rebecca Pallmeyer of the US District Court of Chicago.

He said: “Coming back to Mayer Brown is like coming home for me. I am excited to rejoin the firm’s collegial and exceptionally talented litigation team to help clients navigate the impending uptick in federal enforcement and investigative activities.”

McDonnell is the latest former federal prosecutor to join Mayer Brown in recent years, following the arrivals of former Southern District of New York attorneys Daniel Stein and Glen Kopp, as well as Gina Parlovecchio from the Eastern District. Michael Levy and Jason Linder also made the switch.

Raj De, managing partner of Mayer Brown’s Washington office, said: “Sean has an impressive combination of civil litigation and law enforcement experience. His deep understanding of how to navigate complex government investigations makes him a tremendous asset to the firm’s clients and expanding Washington office, which has welcomed several leading former government officials over the past year.”

A number of US lawyers have been leaving public sector positions this year for opportunities in private practice. Last month, Arnold & Porter hired former SEC whistleblowing chief Jane Norberg to boost its securities litigation team in Washington. Also in May, Winston & Strawn hired former Department of Justice lawyer Jonathan Brightbill to strengthen its Washington environmental litigation team.