The 26-year-old had the choice of playing for either nation early on in his career, but decided to go north of the border to honour his Scottish grandfather - and has since won 23 caps for the nation.
"I had the chance to go and play international football for Scotland at a young age and I've never regretted it because it's been great," he told The Guardian.
"I've played against Brazil and Spain a couple of times, great occasions at Hampden Park, and I've been one of the top players there.
"The reason I went with Scotland was because my grandad, George, was Scottish and he always wanted me to do it. He passed away and I did it on his behalf.
"Also, I didn't get picked for [England] Under-21s, so I thought: 'Sod it, my chances don't look that good'."
Morrison has since played for current England boss Roy Hodgson at West Brom, and the former Middlesbrough man has nothing but praise for the Three Lions manager.
"Roy was a special guy and he taught me a lot: how to play midfield on the defensive side: backing up play, shuffling across, blocking up lines," Morrison added. "He was very interesting, like one of those experienced men you see in a pub sometimes who you can go to for a chat.
"And he never missed a thing. When he first came in, he was always shouting: 'I can see you're walking, you're not doing it.'
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"All the lads came off the training pitch sweating, thinking we'd never worked that hard before. Roy probably laid a lot of the foundations at West Brom. He's a real good man and I've got a lot of respect for him."
So improved were Morrison's performances under the tutelage of Hodgson and now Steve Clarke at West Brom, BBC pundit Garth Crooks said of the midfielder: "This is a player Roy Hodgson should now be taking a keen interest in" - despite the Darlington-born man having already notched up more than 20 appearances for the Tartan Army.
Morrison took the mis-understading about his international career well, however, admitting: "There was laughter," before conceding: "some bad publicity is good publicity really. A lot of people said to me: 'You must be doing something right if he's picking you to play for England'. But I was laughing, saying: 'I've got 23 caps for Scotland'."