Last week the province's anti-corruption squad issued an arrest warrant for Porter and others involved in building a new superhospital in Montreal. Porter has denied the charges he faces, including fraud, conspiracy to commit fraud, fraud toward the government, breach of trust, participating in secret commissions and laundering proceeds of crime.
Couillard's relationship to Porter has been the focus of some criticism, especially during the provincial Liberal debates when he was questioned by his competition about the nature of his dealings with Porter.
"While we were fighting corruption, making laws and fighting tax evasion what did you do, you were there partnering with Arthur Porter and working in Saudi Arabia," said candidate Raymond Bachand during the English debates.
On Tuesday, Couillard responded to the criticisms in a conversation with CBC's Daybreak.
"I've never made a mystery of the fact that I knew him – a lot of people had admiration for his life story, for his professional accomplishments; he did accomplish a lot in Montreal," Couillard said.
He said he is the victim of a smear campaign and he never went into business with Porter.
"People have to realize that we're less than two weeks from the day of the vote," he said.
"I'm not surprised by this … it's part of an organized campaign."
Couillard says he has nothing to hide and he has no connection to the charges Porter faces.
The provincial Liberals will choose their next leader on March 17.