It is A.C.Milan.
Arsenal Football Club has the second most number of league trophies.
Manchester United
The Italy League winners of 1936 were Bologna Football Club.
The Italy League winners of 1905 were Juventus Football Club.
The Italy League winners of 1931 were Juventus Football Club.
The Italy League winners of 1932 were Juventus Football Club.
The Italy League winners of 1933 were Juventus Football Club.
The Italy League winners of 1937 were Bologna Football Club.
The Italy League winners of 1939 were Bologna Football Club.
The Italy League winners of 1949 were Torino Football Club.
The Italy League winners of 1950 were Juventus Football Club.
The Italy League winners of 1960 were Juventus Football Club.