Stretford had appealed against a regulatory commission's sanctions imposed in July after seven of nine charges of breaching Fifa and FA regulations were found proved.
An independent appeal board announced that they had upheld the original punishment on Monday.
A statement said: "The board dismissed Mr Stretford's appeal in its entirety and the decisions of an independent regulatory commission in July 2008 were confirmed."
Stretford can still go to an arbitration panel to contest the findings and his ban will be suspended until he has made that decision.
In their findings, the appeal board said: "We are entirely satisfied that the overall penalty was not excessive and was well within the range open to a reasonable regulatory commission considering matters of this seriousness."
The commission had ruled Stretford, founder of Proactive Sports Management which became the Formation Group four years ago, "muscled in" to persuade Rooney to breach his representation contract with previous agents Pro-Form.
Other charges included improper conduct, in relation to Stretford's "making of false and/or misleading witness statements to police and giving false and/or misleading testimony to Warrington Crown Court" about the circumstances of how he came to represent Rooney.
After the hearing in July, Stretford labelled the verdicts "a travesty".
Stretford will only serve half of the suspension if he is not found to have broken further regulations.
He became Rooney's agent in September 2002, helping the striker transfer from Everton to Manchester United two years later.
The charges concern evidence Stretford provided to a court in October 2004 in which three men were accused of blackmailing him in 2003.
A judge threw out all charges against the men, while Stretford was found to have made false statements to the court and was declared an unreliable witness.
Stretford said during the trial that he signed Rooney in December 2002. However, documents showed he had signed him three months earlier when the player was still under contract to his original agent, Peter McIntosh.
The FA also found that Stretford had signed Rooney to an eight-year contract, exceeding the maximum limit of two years.
Two additional charges of failing to lodge representation contracts with the FA were also proven, though a third was not.(telegraph)
