He was born Peter Sydney Ernest Aylen.
He made his acting debut at age 7.
At the age of 14, he severely injured his right arm in an accident when it went through a glass door. The injury greatly compromised the use of his lower arm and hand with irreversible nerve damage, which he later learned to hide.
With heartthrobs such as Clark Gable and stalwarts like James Stewart off to WWII, he was recognized as the romantic lead on the MGM lot.
He was a part of the Rat Pack and the one that brought the project of Ocean's Eleven to Sinatra.
His was JFK's brother-in-law.