Mr Grade is a keen Charlton supporter and season ticket holder who acquired a stake in the club in the early 1990s when it was redeveloping its ground at the Valley in south London.
Charlton is planning a listing on the Alternative Investment Market which will raise around pounds 6m to continue the development of the Valley into a 20,000 all-seater stadium.
Commenting on the appointment of Mr Grade, who recently quit as head of Channel 4 to become chairman of First Leisure, Charlton chairman Richard Murray said: "His experience of the television and leisure sectors will be invaluable to us as we work to implement our plans to develop Charlton."
He said the planned 8,000-seat stand at Charlton would have space for other facilities, such as a gym or a bowling alley, on which Mr Grade might be able to advise.
Mr Murray said that Charlton's gates had risen by 58 per cent since the club returned to its own ground. He said the club would be profitable this year.