The Scot had a hard act to follow in Roy Hodgson, who guided Albion to a top-10 finish in the Barclays Premier League last season.
Morrison said: "Look where we are. The gaffer has done fantastic.
"Roy did a fantastic job here but Steve came in, made some good signings, and also had a good group of players.
"Everyone who steps on that pitch gives 100% and that has been the key of this season.
"At the start of pre-season he said he wasn't going to change much because it didn't need changing.
"He tinkered a little bit, but that was about passing the ball a bit more and getting up the pitch a bit more. It seemed to work."