Sinfield, who returned to Leeds last July, is staying on as England rugby director in a consultancy role.
His new deal runs until 2022.
Jamie Peacock, who is a member of Rhinos’ marketing department, has also signed an extended contract as England team manager, until 2021.
Former St Helens star Paul Sculthorpe has been appointed England pathways coach, meaning he will be working with all teams in the England performance unit and focusing on the country’s outstanding young players, from junior academy to Knights level.
Paul Anderson will be continuing as Knights head coach in a consultancy role after joining Warrington’s backroom staff since the end of last season and former Warrington forward David Elliott remains national programme manager and head coach of the England academy team.
Ben Jones, previously research and innovation manager, takes a new role as England performance director; Jane Phillips takes over as head of England operations; and Barry Frost continues as head of performance analysis.
Ralph Rimmer, the RFL chief executive, said: “We created the England performance unit last January after proposals from Kevin Sinfield, and the results for 2018 speak for themselves.”