The 47-year-old wrestler turned Hollywood actor made a surprise appearance at the promotion's Money in the Bank pay-per-view event in Toronto on Saturday night.
He announced he will step away from wrestling after a retirement tour where he'll perform at signature shows Royal Rumble, Elimination Chamber and WrestleMania.
The 16-time world champion, arguably the greatest-ever WWE superstar, also said he wants to be involved when WWE's weekly Monday Night Raw show moves to Netflix in January.
Cena's presence in the WWE has massively reduced in recent years as he sought success in movies and TV.
Speaking in the ring on Saturday night, Cena said: 'Why am I here? Tonight I officially announce my retirement from the WWE.
'I hear a mixed opinion out there. A lot of questions maybe, right? Like, why here? I want to talk about that for a second. I want to talk about Toronto. Matter of fact, I want to talk about Canada. Matter of fact, I want to talk about Canadians.
'I've been doing this a while. I've been in WWE for over two decades and in that time I've seen incredible waves of prosperity like we got right now. WWE is the hottest ticket in town, no doubt.
'And I've also seen tremendous hardship and that's when nobody knows your name, nobody wants to be your friend and only the most dedicated, hardcore fans stand by your side.
'So in all those years one of the most important, one of the most impressive things that I learned was whether the WWE was hot or cold, Canadians always show up.
'All of you built this to what it is today which makes this, in my mind, the perfect place to say what I've got to say.
'This farewell does not end tonight. It is filled with opportunity. Everybody, RAW makes history next year when it moves to Netflix. I've never been a part of RAW on Netflix. That is history. That is a first and I will be there.
'Along with that history-making first, we are going to build so many unforgettable lasts.
'The 2025 Royal Rumble will be my last. The 2025 Elimination Chamber will be my last and I'm here tonight to announce that WrestleMania Las Vegas in 2025 will be the last WrestleMania I compete in.
'I know, I know. That's a lot to take in. Probably a lot of questions out there, which is why I'm telling you right now I am going to kick off the press conference right after the show and I will be fielding any and all questions to do with my retirement.
'I want to say thank you. What an incredible gesture of kindness. I want to say thank you. Thank you so much for letting me play in the house that you built for so many years.
'Thank you so much always for your voice, because it's really loud and your honesty because it's beautifully brutal. and most of all thank you so much for allowing me to be here with you tonight to let the world know we are planning something unforgettable which also involves me returning to Toronto to kick some a**.
'So if you are watching at home or here in Toronto or if you're a WWE superstar, if you want some hurry up and come get some because the last time is now.'
Cena, who walked out naked at the Oscars in March, is level with WWE legend Ric Flair for the most world titles in wrestling history with 16.
He's been at the heart of many of the company's legendary storylines in the past 20 years, battling the likes of Dwayne 'The Rock' Johnson, Triple H, Brock Lesnar and Randy Orton.
Cena's acting career has taken off in recent years. He starred in the Fast and Furious franchise, as well as Barbie, Daddy's Home and Trainwreck.
He's also hosted Saturday Night Live and the ESPY's and is currently starring in Peacemaker on HBO.
DM