Moe Howard was neither the first nor the only person to wear a bowl cut. According to Fashion Encyclopedia, the style was big in Europe between the 12th and 15th centuries. It was done by simply placing a bowl on the cuttee’s head and slicing around the rim. It worked for both the religiously pious, who didn’t want to spend money on elaborate hairstyles, and for the poor, who couldn’t afford to pay a barber.
The haircut’s association with poverty meant that it eventually went out of style. To this day, people rarely wear it unless they absolutely have to. That, or they’re wearing it ironically and/or for comedic purposes. For Moe, the haircut came out of a botched attempt at cutting his own hair as a small child, and it became part of his signature look when he went into show business.