Charlie Angus said the judge's decision shows officials at ACOA "bent the rules" to protect Kevin MacAdam, who has ties to the Conservatives.
"That means that while hard-working Canadians and senior citizens are being told the cupboard is bare, they are stuffing the trough with their Tory friends," he said in the House of Commons.
Gerald Keddy, the parliamentary secretary to the minister responsible for ACOA, said the Public Service Commission will review the judge's decision and advise the agency of the next step, although he didn't elaborate.
A spokesman for ACOA couldn't comment on whether MacAdam is still employed by the agency.
Earlier this week, a Federal Court judge dismissed an application from MacAdam, a former Progressive Conservative cabinet minister in Prince Edward Island, after he filed for a judicial review of a Public Service Commission decision to quash his appointment to ACOA.
He was named director general of ACOA in P.E.I. in February 2011, provoking opposition criticism from the Liberals that the federal Tories were making patronage appointments at the agency. He filed for the judicial review in Federal Court in 2012.
MacAdam served in the cabinet of former P.E.I. premier Pat Binns and once worked on the staff of Justice Minister Peter MacKay when he held the Defence and ACOA portfolios.
In a decision released Monday, Judge Richard Mosley dismissed MacAdam's application.
In his ruling, a copy of which was provided by the federal Liberals, Mosley said revoking MacAdam's appointment was "a recognition of the fact that the appointment process was tainted as a result of improper conduct and therefore the appointment itself was void."
Mosley also said there's no indication that MacAdam acted improperly.
"This is not to suggest that Mr. MacAdam was not qualified for the position," he wrote. "It is unquestionable that he knew the economic conditions on the island well and was very familiar with the ACOA process both from his prior experience as a provincial minister and five years working for the responsible federal minister."
The decision goes on to say MacAdam may have been named to the job in a fair competition for the position.
"But any likelihood of that outcome does not answer the commission's conclusion that improper conduct helped him get the job," Mosley wrote.
Note to readers: This is a corrected story. A previous version said the judge threw out a bid to overturn a commission decision on his hiring.