John Alexander embarked upon his theatrical career at the tender age of sixteen, when he joined a prestigious Shakespearean repertory company. This marked the beginning of a long and illustrious journey, which would ultimately see him tread the boards of Broadway for the very first time in 1917, taking on the role of a character in the esteemed production of "The Merchant of Venice".
Throughout his extensive and varied career, John Alexander would go on to play a multitude of parts on both the stage and in films. However, it was his iconic portrayal of Teddy Brewster, a character who harbored the delusion that he was none other than the esteemed Theodore Roosevelt, that would cement his place in the annals of history. This unforgettable performance, which he delivered with aplomb both on stage and in the cinematic adaptation, would forever be etched in the minds of audiences and critics alike.