Roberts helped Wales retain the 6 Nations title in March and then scored a try in the deciding match as the Lions completed an historic Test series victory over Australia
The 26-year-old has spent the last eight years juggling his medical studies with his rugby and he sat two exams in the week before the Six Nations title decider against England.
Roberts extended the final two years of his degree to four years so he could make the most of his rugby career, which often meant training in the morning and working in a hospital in the afternoon.
Speaking after his graduation, Roberts told Media Wales: "Ultimately, you work hard and achieve your goals and I've managed to do that over the last eight years.
"It's been very tough balancing everything and ultimately it's about trying to focus when you're tired.
"That physical demand of rugby versus the mental demand of medicine is a big war you're playing out in your head.
"As I said you reap the rewards with everything you do in life. I've had some very challenging times, some tough times, no more than the Six Nations, but I'm very proud today."
Roberts will start a new chapter in his rugby career next season when he joins Racing Metro in Paris.