An enduring hit here and across the Atlantic, Brown Eyed Girl — captured on its 22nd take — has now been played on radio in the US 10 million times, earning the Belfast man special recognition at the Broadcast Music Inc awards in London this week.
But mystery still surrounds the inspiration for the song that Morrison now claims wasn't one of his best.
“I've got about 300 songs that I think are better,” he was quoted as saying in a recent interview.
But just who was the Brown Eyed Girl, the former lover who inspired him to write?
According to Morrison, the single, produced by Bert Berns and first released in mid-June 1967, was originally entitled Brown Skinned Girl.
Morrison changed the name to Brown Eyed Girl when he had finished recording it.
Remarking on the original title, he said: “That was just a mistake. It was a kind of Jamaican song... Calypso.
“It just slipped my mind. I changed the title.”
He continued: “After we'd recorded it, I looked at the tape box and didn't even notice that I'd changed the title. I looked at the box where I'd lain it down with my guitar and it said Brown Eyed Girl on the tape box.
“It's just one of those things that happens.”
The song may have been about a Belfast girl, but Stuart Bailie of the Oh Yeah Centre thinks the singer may have been using poetic licence.
“I'd like to think it's about Belfast and that the stadium he refers to may have been The Oval in east Belfast.
“Although it could have been the Shankill Stadium as well.” Radio Ulster's Ralph McLean said: “Morrison's songs are best when full of intrigue.”
At the time of its release, the song's nostalgic lyrics about an ex-lover were considered too explicit to be played on many radio stations.
A radio-edit of the song was released which removed the lyrics “making love in the green grass”, replacing them with a line from a previous verse.
The edited version appears on some copies of the compilation album The Best Of Van Morrison.
One source said: “Depending on who you talk to, there are many different versions of who this woman could have been.
“But maybe we'll never know.”
The song was recorded during a two-day session with Berns at A&R Studios in New York.
When it was released, Morrison was only 22 and his solo career, post-Them was still in its infancy.
It became his first American Top 10 single and, according to BMI spokesperson Robin Ahrold, has since “transcended hit status”.
“It's into a very elite status where if you go for a meal in a restaurant you're likely to hear it played at some point,” he said.
“It's definitely a standard that gets airplay all the time, year in, year out.”
But Van Morrison still has some way to go to catch up with the act with the most airplay in US radio history.
The Righteous Brothers' You've Lost That Lovin' Feelin’, produced by Phil Spector, has been heard almost 15 million times — and is still going strong.
In January 2007 Brown Eyed Girl was inducted into the Grammy Hall of Fame.
In November 2004 it was listed at 109 on the Rolling Stone magazine list of 500 Greatest Songs of All Time.
It’s one of The Rock and Roll Hall of Fame's 500 Songs that Shaped Rock and Roll.
In 2000 it was listed at 21 on Rolling Stone and MTV's list of 100 Greatest Pop Songs, and it also was listed as 49 on VH1's list of the 100 Greatest Rock Songs.