George Galloway, an activist opposed to the Middle East conflict, was turned away in March 2009 because of his support for the Palestinian Hamas party, which the Canadian government considers a terrorist group, the Toronto Star reported.
He landed at Toronto's Lester B. Pearson International Airport Saturday afternoon and was detained for questioning for about an hour before being released, Postmedia News said.
Some 100 supporters cheered when he was released, reports said.
"I'm very happy to be here in Canada and my presence here proves that Canada remains a country governed by laws and not by 'here today, gone tomorrow' politicians," he said, referring to Immigration Minister Jason Kenney, who blocked his last visit.
The former Labor Party parliamentarian lost his seat as a result of the publicity over his last attempt to enter Canada and Galloway said he is considering legal action against Kenney and the Canadian government.
"I have been defamed in a way which is scarcely possible to exaggerate," he said. "For a high-profile politician to be announced to the world as a terrorist … placed my life in danger."