According to Dior, the logo was created in a single afternoon. Contrary to popular belief, the silhouette was not modeled on future Hall of Famer Harmon Killebrew, or any specific player but was drawn with reference to photographs of several players. The silhouette was chosen specifically because of its ambiguity: the batter could be right- or left-handed and of any ethnic background. 
For many years, the authorship of the logo was a matter of some dispute as two graphic designers laid claim to creating the piece: Jerry Dior (working for the marketing firm of Sandgren & Murtha) and James Sherman, who is probably better known publicly as a comic book illustrator. In November 2008, ESPN writer Paul Lukas managed to clear the matter up and Dior's authorship is no longer in doubt. Upon closely examining the logo, Sherman declared:
"That's not my logo, and I was totally unaware that it existed... The logo I created was very similar, but I designed it in the early 1980s. All I can say is that I was so sports-unaware that I didn't know about the earlier logo. I feel like a total idiot now that I didn't know about it. I'm flabbergasted."
The logo has not been changed in the years since its adoption, except that individual teams sometimes alter the coloring to match their uniform colors. Since its adoption, the basic model of an athlete (or equipment used for the sport) in silhouette flanked by red and blue color blocks has also been incorporated in the logos of the National Basketball Association (with Jerry West as its player model), Minor League Baseball, Women's National Basketball Association, Arena Football League, Hockey Canada, American Hockey League, PGA Tour, National Lacrosse League, Indy Racing League, and Major League Gaming. It has also been parodied in Major League Eating.
Alan Siegel, who oversaw Dior's logo, deliberately based his NBA logo design off the MLB's in 1969 because NBA Commissioner J. Walter Kennedy wanted a family relationship between the sports seen as being All-American.