The wild cliffs of Cornwall seem a million miles from the leafy grounds of his alma mater.
His biggest credits so far come at the climax of the first season of costume drama Poldark, a brooding gallop through 18th Century turmoil with an acclaimed final episode.
His previous work includes Pepsi's 2014 Super Bowl advert, while he is currently working on his first feature film - a gothic fairy story set in the Welsh mountains.
Today Mr McGregor, 27, who grew up in East Rudham, visited staff and students at the college and its neighbouring academy.
'It's a massive wave of nostalgia,' he said. 'I saw my old geography teacher, Mr Bye. Going to school in the countryside, surrounded by landscape and nature, was something I didn't appreciate at the time, but looking back on it you do.'
Mr McGregor gave presentations to the current crop of film studies students on both campuses.
'I never considered when I was at school that directing TV or films was even a possibility,' he said. 'So it's just to say that if you want to do it, you can do it.'
A college trip to New York and a teacher who gave him a flyer for a student film competition helped inspire him to go on to study at the University for the Creative Arts in Surrey. Despite a steeply upward career trajectory, he said he was surprised at the success of Poldark - the original of which was on our screens decades before he was born.
'You hope it's going to do well, but you never know,' he said. 'It's great to see it do well.'
Lianne Higgins, head of college, said visits from alumni were inspiring and informative.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here