Wales international Morison struggled against England's Three Lions last weekend but found the Tigers more to his liking with a superb finish.
He latched onto Liam Trotter's clever through ball and expertly dinked it past Brad Guzan to keep Millwall's play-off hopes alive.
"It was a good performance. First and foremost we defended very well and limited hull to very few shots and opportunities," said Jackett.
"In the second half we could have done a little bit more with the ball to kill the game off, but that's being hyper-critical. To come up to Hull at this stage of the season and win is a very good achievement."
"Steve's goal was excellent. I've seen him score like that in training with his right foot, but to do that with his left and give the goalkeeper no chance was very good. His form has been very good and I was very impressed with his teamwork and his overall work ethic."
Source: PA
Source: PA