New Milford police say 49-year-old borough resident Sanjiv Agarwal was charged with assault.
Authorities say Agarwal arrived late for the New Milford High School ceremony, which was staged at another school.
Citing fire codes, attendees were barred from standing in the rear or aisles of the school's auditorium once the room reached capacity. To accommodate the overflow crowd, live-stream video of the ceremony was available in two classrooms.
After being told he couldn't enter the auditorium, authorities say Agarwal tried to force his way in by pushing teachers and guests. After ignoring directives to leave, he allegedly punched one officer as police tried to physically remove him.