The appeal sought to restore a lower court ruling, which last year found Ford in a conflict and ordered him removed from office.
That finding was overturned earlier this year by an appeal panel.
As usual, the Supreme Court gave no reasons for refusing to hear the case.
"I'm so happy this is finally over," Ford said at city hall in Toronto.
"I'm vindicated and we can move on."
The matter dates to 2010, when Toronto's integrity commissioner ruled that Ford — at the time a city councillor — had abused his position by using official letterhead and other council resources in fundraising letters which generated $3,150 for his football foundation.
The council discussed the matter and voted to order Ford to return the money, only to reverse itself last year with Ford, as mayor, voting in his own favour.
Toronto resident Paul Magder initially succeeded in his filing to have Ford declared in conflict and ousted from office. However, the judge's decision was overturned on appeal on a technicality.
As he had done previously, Ford railed at "political activists" who "tried to abuse a loophole and outdated laws" in bringing the case forward.
"The entire case was driven by the agenda of a very small group," Ford said.
"They couldn't beat me at the polls, so they tried everything."
Ford recently made international news when U.S. website Gawker and the Toronto Star reported seeing a cellphone video appearing to show the mayor smoking crack cocaine.
The mayor has said he does not use crack and the video does not exist.
Gawker raised $200,000 to buy the alleged video that was reportedly being shopped around by a drug dealer, but so far has had no success in obtaining it.
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