On April 9th, 1945, the NFL officially mandated that all players must wear long stockings covering their lower legs. This decision, spearheaded by Commissioner Elmer Layden, aimed to create a more uniform and professional aesthetic across the league. While seemingly a minor detail, this rule has persisted for decades, directly influencing the visual presentation of NFL players on the field every Sunday.

This "sock up" mandate, established on April 9th, distinguishes the NFL's uniform policy from many college football programs where bare legs are still common. The enforcement of this rule, often resulting in fines for violations, underscores the league's commitment to a consistent and polished appearance. It's a subtle yet defining characteristic of the NFL's iconic visual identity, a tradition upheld for over three-quarters of a century.