Dan Cleary scored for Detroit (2-3-1) in the tiebreaker.
Viktor Stahlberg had two goals and an assist and Nazem Kadri and Mikhail Grabovski also scored for Toronto (5-2-0). Jonas Gustavsson stopped all seven shots he faced in the first period, and Vesa Toskala made 29 saves.
"I don't thin we were as sharp as you have to be to play in this league," Red Wings captain Nicklas Lidstrom said. "Especially in our own zone."
Grabovski tied at 4 for Toronto with 1:11 left in regulation.
Franzen's power-play goal tied it at 3 with 8:05 left in the third period, and he made it 4-3 with 7:51 left when he stole the puck from Garnet Exelby behind the net, brought it to the bottom of the right circle and beat Toskala with a wrist shot.
Kronwall's first goal put Detroit on the board with 5:07 remaining in the middle period, and he made it 3-2 7:16 into third period on a one-time slap shot.
"We fell apart for a couple of minutes in the third," Stalberg said. "A few mistakes, which is easy to do against the Red wings when they're pressuring."
Kadri gave the Maple Leafs a 3-0 lead with 9:32 left in the second period and the teams playing 4-on-4. Stalberg's goals gave Toronto a 2-0 lead after the first period.
"We're trying to get ready for the season," Red Wings coach Mike Babcock said. "We've got to play better."
Copyright by STATS LLC and The Associated Press
Arena: Joe Louis Arena Location: Detroit, Michigan
Attendance: 14,399 (71.8% full)
Viktor Stahlberg Assist: Christian Hanson, Tyler Bozak