The celebrity publicist said he was approached several months ago. The performer was cleared of child abuse charges on Monday.
'I was asked to take on Jackson,' Clifford told PRWeek. 'Whoever takes him on deserves a PR Oscar - the task of rebuilding his reputation is near impossible.'
Clifford, who represented the Jackson Five from 1967 to 1969, said Jackson lacked the personality to come across well on television.
'He has to convince people that he is a different person from the one that people have seen in recent times, in the trial and in the interview with Martin Bashir.
'His fans love him no matter what but they are not going to make him a massive star again,' he added.
However, The Outside Organisation head of corporate Jonathan Morrish - who represented Jackson for 25 years at Sony Music until 2001 - said: 'He can rebuild his reputation by going on tour in Europe or the Middle East, where his strongest markets are.'
Jackson is reported to be considering a performance at one of the Live 8 concerts.