With the win -- in which they rallied from two goals down -- the Blackhawks gained the Stanley Cup championship round for the first time since 1992. They will face the winner of the Eastern Conference Finals between Philadelphia and Montreal.
The Flyers hold a 3-1 edge in that series and could wrap it up with a win in Monday's Game 5.
Bolland's goal with less than 2 minutes left in the second period tied the contest 2-2, and Byfuglien's power-play tally on assists from Patrick Kane and Jonathan Toews gave the Hawks the winning advantage.
Kris Versteeg added an empty-net goal and notched an assist. Chicago netminder Antti Niemi made 18 saves and faced only three shots in the final stanza as the Hawks clamped down on defense.
Chicago holds the current mark for the longest span without winning a Stanley Cup -- their last NHL championship came in 1961.
Logan Couture and Patrick Marleau scored for the Sharks in the season-ending loss.