Miles Heizer

That’s not exactly the body I would think of when I think of a Marine, though maybe it fits the concept of Baby Blue Marine, which I don’t exactly know what that means, but I imagine someone more boyish than manly.
 
That’s not exactly the body I would think of when I think of a Marine, though maybe it fits the concept of Baby Blue Marine, which I don’t exactly know what that means, but I imagine someone more boyish than manly.
I think he fits the bill. "Set in 1990, The Corps follows charming underdog Cameron Cope (Heizer), a bullied, gay high school student who impulsively joins the Marine Corps".

To be a marine the minimum height and weight requitement is 5'6" and 170lbs. You don't need to be the Big, burly man movies depict marines as. Heck just like other branches of the US military you could end up with a desk job.

Never heard the phrase "Baby Blue Marine" but it's apparently a derogatory term for someone who didn't make it through training and isn't actually a marine.