Purslow will remain at the club in a non executive director role and will act as a special advisor to the new owners.
Former owner Tom Hicks had criticised Purslow for his involvement in the NESV deal and it was revealed he attempted to remove him from the club’s board to prevent the deal going through.
In a statement on the club’s official website, New England Sports Ventures chairman Tom Werner said: "We are delighted Christian has accepted our offer to help us and the club, given his great experience and love for Liverpool FC. We will now begin a global search process for a chief executive officer."
Purslow added: "I came to LFC to lead the club through a sale process to get the best overall deal including, vitally, the removal of the debt. I am immensely proud of what we have all achieved. I now look forward to assisting the owners in any way I can at this exciting time as they drive the Club forward to a bright future."
Chairman Martin Broughton is also expected to leave his post soon following the takeover.