Alongside fellow bronze medalist Karl Aage Hansen, Sørensen joined Atalanta of Bergamo in the Serie A championship of Italian football. It was through Hansen's recommendation, that Bergamo hired Sørensen. In his first time at the club, Bergamo played a friendly match against Sørensen's old club Odense on Odense Stadion. Sørensen was leading the Bergamo players onto the pitch, but as Karl Aage Hansen held back the other Bergamo players, Sørensen entered the pitch on his own to waves of applause from the Odense fans. Sørensen spent four seasons at Atalanta, scoring 51 goals in 134 games, and played alongside fellow Danish international players Svend Jørgen Hansen and Poul Rasmussen at the club. He moved to league rivals A.C. Milan in 1953, and played two seasons with the club, scoring 28 goals in 64 games. He won the 1954–55 Serie A championship in his last season with Milan, before leaving the club in 1955. Milan offered him a contract extension, but Sørensen decided to return to Denmark. He was selected for a European Representative team to play against a Great Britain team to mark the 75th anniversary of the Irish Football Association in August 1955. Sørensen worked defensively to neutralize English player Sir Stanley Matthews, and the European team won 4–1.