Berruti was born in Turin where he attended Liceo Classico "Cavour". After high school, while pursuing an undergraduate degree in chemistry, he competed in the 1960 Rome Olympics. In the semi-finals of the 200 m, spurred by the home crowd, he unexpectedly ran in 20.5 seconds, equalling the then world record for that distance. This made him a surprise outsider for the final, later that day. In that race, Berruti, who was noted for always running with black glasses and white socks, once again clocked 20.5, beating the American favourites to the gold medal.
Anchoring the Italian 4 x 100 m relay team, Berruti narrowly missed out on a second Olympic medal, finishing in 4th. His world record was not beaten until June 1962, but his performance remained a European record for a further two years, until 21 June 1964.
His Olympic victory, at the beginning of his career, would remain his best achievement. His three appearances at the European Championships only brought him a 7th place in the 1966 200 m final. He did, however, win Italian titles in both the 100 and 200 m from 1957 until 1962, and two more 200 m titles in 1965 and 1968. Berruti also made two more Olympic appearances, in 1964 and 1968. On both occasions, he reached the final of the 4 x 100 m relay, and also placed 5th in the 200 m final of 1964.