Johnson played more than 300 games in his Tigers career and will take over in his new RFU role on July 1 on a contract covering beyond the 2011 Rugby World Cup.
Tom, who saw Johnson come through the Tigers ranks to captain the team to four successive league titles and back-to-back Heineken Cups before leading England to the World Cup triumph in 2003, said: "On behalf of everyone associated with Leicester Tigers, I offer my congratulations to Martin Johnson on his appointment as England team manager.
"Martin had a fantastic record as a player and captain with Leicester Tigers, England and the Lions, and he commands respect throughout the rugby world.
"I have no doubts whatsoever that he will be a massive success in his new role. We wish him and his England team well for the future."
Fellow former Tigers forwards John Wells and Graham Rowntree are also involved in the England coaching team.