What was Johnny Cash's first single released on Sun Records, what month and year?

That would be Cry, Cry, Cry and the date is June 21, 1955. Great song!!!!

Everybody knows where you go when the sun goes down.

I think you only live to see the lights of town.

I wasted my time when I would try, try, try.

When the lights have lost their glow, you're gonna cry, cry, cry.

I lie awake at night and wait 'til you come in.

You stay a little while and then you're gone again.

Every question that I ask, I get a lie, lie, lie.

For every lie you tell, you're gonna cry, cry, cry.

You're gonna cry, cry, cry and you'll cry alone,

When everyone's forgotten and you're left on your own.

You're gonna cry, cry, cry.

Soon your sugar-daddies will all be gone.

You'll wake up some cold day and find you're alone.

You'll call to me but I'm gonna tell you: "Bye, bye, bye,"

When I turn around and walk away, you'll cry, cry, cry,

When your fickle little love gets old, no one will care for you.

You'll come back to me for a little love that's true.

I'll tell you no and you gonna ask me why, why, why?

When I remind you of all of this, you'll cry, cry, cry.

You're gonna cry, cry, cry and you'll cry alo

Hank, you need to become a fan of Wikipedia.

His first recordings at Sun, "Hey Porter" and "Cry Cry Cry", were released in 1955 and met with reasonable success on the country hit parade.

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June 21, 1955, A-side "Cry! Cry! Cry!", B-side "Hey Porter!"