The story is told in Burton Hersh's _The Education of Edward Kennedy_.
In the spring of 1951, freshman Teddy Kennedy has a Spanish A final to take. One of his football teammates had a roommate who knew the language very well -- they called him "The Master of Spanish." Someone joked that the Master should take Teddy's exam for him.
On a whim, the Master agreed. Unfortunately, the Spanish A exam proctor recognized him. Within minutes of the exam's conclusion, Kennedy got a call from Dean of the College Delmar Leighton's office. He was nailed: Immediate suspension, readmission to be considered after at least one year off.
Teddy ended up enlisting in the Army during his time off. After 16 months of service, he returned to Harvard in 1953. From that point on, he trod the straight and narrow, and graduated in 1956 with a B average.
Happened before I was born, glad to hear the details......all I can remember is my parents discussing this scumbag as I was growing up. I vaguely remember Chappaquiddick.........(obviously, my parents raised me right; I recognize scum when I see it.)