The Blackhawks went 2-for-4 with the advantage. Kane, the NHL's rookie scoring leader and first overall pick in the 2007 draft, also recorded an assist.
Rene Bourque scored short-handed and Yanic Perreault added an empty-net goal for Chicago. Goalie Patrick Lalime, making consecutive starts for the first time this season, blocked 23 shots to help the Blackhawks win their second straight.
"Our power play was awesome for us again," Chicago coach Denis Savard said. "The first 30 minutes we were very good - not that we weren't good in the last 30 - but in the first 30 it was just good puck management."
The Blackhawks pressured St. Louis and goalie Manny Legace early. He made 27 saves, including numerous tough chances, to keep the game close.
After the Blues cut Chicago's lead to 3-2, Lalime helped keep St. Louis at bay until Perreault fired in the clincher with 1:03 left in the third period. Lalime who played for the Blues in 2005-06, faced his former teammates for the first time since joining Chicago last season.
"When we needed goals, the power play was there again," Lalime said. "It's fun to be part of this, to be contributing."
"We were coming back and were challenging them hard in the third period," St. Louis coach Andy Murray said. "Legace made some good saves early then their guy made some good saves in the third period. Both goalies had their moments."
Chicago dominated the first period and took a 2-1 lead while outshooting St. Louis 15-7.
After Legace made several point-blank saves to keep it scoreless, Wagner gave the Blues a 1-0 lead with 8:33 left on a screened power-play goal from the left point.
"When we scored to make it 1-0, I though it would turn it around," Legace said, "but it didn't."
Kane and Vandermeer scored power-play goals late in the period.
Kane skated down the slot after beating St. Louis defenseman Bryce Salvador and tied it 1-all with 4:06 left in the first. Legace said the rookie's shot first hit his toe, then skipped in off his catch glove.
Vandermeer's screened shot from the top of the slot got past Legace with 1:11 remaining in the period.
Bourque got credit for a short-handed goal 16 seconds into the second to give Chicago a 3-1 advantage. Duncan Keith's shot from the left circle deflected in off Bourque's abdomen.
Perron's power-play goal from the right circle with 8:43 left in the second cut it to 3-2.
Perreault scored into an empty net with 1:03 left in the third.
- Chicago LW Martin Havlat missed his 15th game because of a shoulder injury, but has resumed practicing with contact. Chicago C Kevyn Adams, who suffered a left knee injury Wednesday against Columbus, said after Friday's game he probably will undergo surgery next Thursday to repair a torn ACL and MCL.
- Blackhawks D Andrei Zyuzin missed his sixth game due to an injured hip muscle and LW David Koci missed his sixth with a broken nose.
- Chicago LW Sergei Samsonov returned to the lineup after sitting five games as a healthy scratch.
- St. Louis C David Backes missed his second game with a knee injury and is expected to be out four weeks.