April 15 is Jackie Robinson Day, which celebrates the day 76 years ago that the legendary player broke the color barrier in Major League Baseball by playing in his first game with the Brooklyn Dodgers.

For 42.

Today, we celebrate the life and legacy of a legend that means so much to our game. Thank you for paving the way, Jackie. #Jackie42 pic.twitter.com/kq6OnEUR1a

— Los Angeles Dodgers (@Dodgers) April 15, 2023

Even casual baseball fans are aware that one way Robinson is honored is that all of the teams don his number “42” on the field today. But how did that tradition start? Here’s the answer.

In an interview the MLB Network’s Harold Reynolds did with Hall of Famer Ken Griffey Jr. in 2021, the former Cincinnati Red/Seattle Mariner reveals the fun story.

Fun fact – every player wears #42 on Jackie Robinson Day thanks to Hall of Famer Ken Griffey Jr. pic.twitter.com/sRxpyMAnPR

— MLB Network (@MLBNetwork) November 21, 2021

Reynolds starts off by saying that “celebrating Jackie Robinson Day is kind of hard to do without talking to Ken Griffey Jr.”

Griffey modestly explains that he wore it “a couple of times” before that as a Mariner. What he leaves out is that he first wore the number at the behest of the Robinson family, while still on the Reds, in 1997:

On the 50th anniversary, April 15, 1997, Major League Baseball held a ceremony prior to the Mets- Dodgers’ game at Shea Stadium. Rachel Robinson, Jackie’s widow, was there, as were MLB commissioner Bud Selig and President Clinton. That’s the day 42 was retired for all teams, although Yankees star closer Mariano Rivera was allowed to continue wearing the number.

In Cleveland, Griffey wore 42 for the Reds in a game against the Indians after being asked to do so by the Robinson family and getting permission from Selig.

It turns out that it was at Griffey’s prompting in 2007 that MLB decided to honor Robinson with the now ubiquitous number “42” jerseys. Griffey tells Reynolds:

Every year, they celebrate [Robinson breaking the color barrier]. And I’m like, ‘How are you going to celebrate something and not wear his number? Honoring it and not wearing the number.

So, I called Bud [Selig] at home. I was like, “Hey, can I talk to you for a minute? Would it be possible if I wore “42” on Jackie Robinson Day?”

Griffey says that he and the then-MLB commissioner chatted for about 10 minutes about the idea. Then Selig asked him whether it would be okay, before he gave the green light on the jersey, if Selig called Robinson’s widow, Rachel, “and make sure it’s okay.” Griffey agreed.

He called me back the next day. He says, “We’re a go, but can everybody wear it?” I said, “The more the merrier.”

Selig understood the importance of everyone wearing Robinson’s number, Griffey says. And although the player never imagined that would be the result of his request, he thinks it was “perfect” that it happened. He admits that “[he] wasn’t thinking that big,” but it’s “been an unbelievable thing since day one.”

Reynolds asks Griffey how it felt when he played his first game “with everybody wearing number 42.” The Hall of Famer likened it to the very beginning of his time in baseball, while playing in Little League:

It was almost like Little League because you know, in Little League the first year, you ain’t got no numbers on your back….[Y]ou’ve got the team name on the front, or whoever you play for on the front….

Then, all of the sudden, you go in there [on Jackie Robinson Day] and look at the line-up card, it just says, “42, 42, 42, 42.” It was very touching and very special.

With a grin, Griffey admits it was “kind of weird,” since many players know their teammates by their uniform numbers. It was a little confusing, at first.

Happy Jackie Robinson Day!