Former Rangers striker Gallen believes that Hasselbaink will prove to be a good managerial appointment for the London outfit.
Hasselbaink was in charge of Burton Albion from November 2014 until last week.
The former Netherlands international striker guided the Brewers to promotion to League One from League Two at the end of last season.
QPR fans will hope that Hasselbaink is able to do something similar at Loftus Road and guide the team back to the Premier League.
Rangers are 12th in the Championship table at the moment with 26 points from 19 matches.
The London outfit are just three points behind Cardiff City, who are currently sixth and occupy the final playoff spot.
A top-two finish is probably beyond QPR now, but they can certainly claim a playoff spot.