Without googling...

[OrangePeppaPig]

Who is Joel Miller...

Could I use it as a name?

For yourself? Sure. For a cat? Bit odd.

For a baby? Or has it made too bigger cultural footprint?

No clue.

Someone from EastEnders?

My BIL

Didn't realise he was famous

Never heard of him but I like it as a name

Dunno

Unless he was one of the characters in that film- We're the Millers or Meet the Millers or something like that.

I've no idea who he is. Of course you can use it for a baby.

Yeah use it OP, never heard of him.

Played loved both but I genuinely didn't know him as anything other than Joel, same with Ellie. I didn't realise his last name was ever mentioned. If you'd have said Troy Baker or Ashley Johnson then I'd have known them.

Who?

I've watched DP play the last of us, neither of us would have known who Joel Miller was and if we heard the name for a baby it wouldn't have even crossed our minds.
Even those who have played it and would recognise it, they'd probably think it a coincidence.