Unveiled at lunchtime on Saturday, the 37-year-old, pictured, will take charge for the first time on Tuesday night when he takes his new charges to Folkestone Invicta in the Ryman's top flight.
Tanners chairman Richard Brady is backing Bullard - one of the stars of the jungle in 2014 on I'm A Celebrity: Get Me Out of Here! - to quickly make his mark in his first management job after succeeding Mike Sandman at Fetcham Grove.
Sandman left on Wednesday with the club second from bottom after collecting five points from their first seven outings and Brady backed his high-profile successor in a statement announcing the news of the Tanners website.
Brady said: "Jimmy has gained a wealth of experience into a variety of management and coaching techniques as a player and is looking to bring the best of these experiences to Leatherhead Football Club, coupled with a very clear philosophy in terms of how he wishes his team to play.
"Jimmy has lived in Cobham for some years, and is excited at the upcoming challenge as well as being very impressed by the state of the art training facilities available at River Lane. Jimmy has held lengthy discussions with me as well as other senior club personnel in order to help in understand the clubs ethos as well as our ambitions for the future that we look forward to him being part of."
He added: "Jimmy will be bringing in support staff, coupled with my help and contacts in the non league football community in order we can look to strengthen the first team squad. I know you will join me in welcoming Jimmy to the club at the very earliest opportunity."
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