McEwen's time of four hours 10 minutes 17 seconds left him 12 seconds behind overall race leader Tom Boonen of Belgium, who finished third in the stage six. Italy's Daniele Bennati was second.
McEwen also won the second and fourth stages of the 2006 Tour de France this week.
American Floyd Landis was eighth overall, 36 seconds behind Boonen.
Celebrity Families of 2014 [PHOTOS]