Wilby’s victory caps a brilliant spell for the Chemistry graduate following his 100m breaststroke gold and 200m breaststroke silver at the Commonwealth Games in July.
The 28-year-old can now add a European crown to his growing collection of medals after another classy performance in Italy’s capital city.
Wilby produced a strong swim to move through the field, taking the title in 2:08.96.
"The whole of the GB team are digging in deep after all the internationals we've had,” he said.
"It's a case of getting in there, being brave and fighting for it. It was a difficult race but I'm really chuffed with the result."
Elsewhere, there were more medals for Loughborough athletes as alumnus Luke Greenbank claimed bronze in the 200m backstroke with a time of 1:56.15.
Anna Hopkin, who trains at the University, was also part of Great Britain’s women's 4x100m Freestyle Relay who won gold, clocking the third-fastest split of the entire race.
Loughborough College learner Jacob Whittle claimed bronze as part of the 4x100m Freestyle, and Wilby and Hopkin also took bronze in the Mixed 4x100m Medley team.
The 2022 European Aquatics Championships are held in Rome between 11 August – 21 August.