But amazingly, it flopped in the UK - only reaching number 42 in the charts when it was released in 1984.
So what happened?
"Ask Radio 1," laughs the star.
"They wouldn't play it. They didn't play Heaven, they didn't play any of my songs [except for] Run To You."
A top five hit in the US, Summer of 69 grew in popularity over the years through exposure on commercial radio and classic rock stations.
Thirty years after it came out, it earned Adams a gold disc, representing 400,000 sales.
Now certified platinum (600,000 sales), it is a karaoke standard with 280 million streams on Spotify - double the number earned by Adams' second most-popular song, Everything I Do (I Do It For You).
"A lot of my songs don't chart but they somehow find their way," Adams tells the BBC. "It's just a matter of time."
Summer of 69 gained a new generation of fans last year, when Adams teamed up with Taylor Swift to perform it as a duet.
The singer has previously admitted the song's title doesn't refer to the year 1969 - when he would have been nine years old.
"A lot of people think it's about the year," he told CBS news in 2008, "but actually, it's more about making love in the summertime. It's using '69 as a sexual reference."
Adams was speaking to the BBC as he releases his 14th studio album, Shine A Light.
He revealed the title track was written "at a time when both my parents ended up in hospital, and I thought I was going to lose both of them".
"I was just trying to write something that was a tribute to them," he said, "and I thought of the idea of shining light everywhere you go".
However, the star struggled to finish the song, until he bumped into Ed Sheeran backstage at a gig in Dublin last year.
Email songwriting with Ed Sheeran
"I was only about half-way through [the song] and I thought, 'I wonder if Ed would want to finish this with me?'
"So I sent it to him and we wrote the song together on email."
"It's an optimistic, uplifting song," he adds. "It doesn't necessarily have to be about my parents.
"It's saying everywhere you go, shine a light - because we are all little lights in our own way."
Shine A Light is set to enter the album charts at number two this weekend - but like Summer of 69, the single has failed to crack the UK's top 40 (despite support on BBC Radio 2).
Despite that, Adams says he thinks the song "is going to have a future".
"I'm not a wizard, I'm just a songwriter. Sometimes, you might feel like you're doing the right thing - but it doesn't necessarily fit what into everyone else thinks is happening, musically."
And he says he's fortunate to still be making music, 41 years after his debut single.
"For me, it's a marvel that the songs have survived - and truly it's the reason why I can continue to tour, because the songs don't rely on support of radio play.
"They've gone on to be big because they're good songs."