Police say the victim was in his 30s and originally from France. His name has not been released. He and his wife were in Canada on a work permit, according to police.
A Toronto police sergeant briefing reporters at the scene said the man was sitting with his wife under the tree when he was struck and killed.
He jumped to protect his wife from the falling branch when it hit him, police said.
His wife has been taken to hospital. There’s no word yet on whether she herself was injured.
City workers were called to the park to assess the health of the trees.