The first case of the quote appeared in the third and fourth chapters of JoJo’s Bizarre Adventure: Phantom Blood, which was the first story arc of the manga, published in 1987.
The popularity of the phrase, however, didn’t come until the scene was included in the anime’s pilot episode, which premiered on October 5th, 2012.
A discussion was immediately started in the anime board of 4chan.
“It was me, Dio” has appeared several times on 4chan, both in the form of a screenshot, as well as a quote.
In 2014, photoshop edits and reiterations of the meme started showing up on Tumblr as well as Twitter.