I think this role is deceptively difficult to cast. Armstrong is a famous man and an icon of the space age, but he’s also something of a phantom, notoriously reclusive (with respect to the media that is, not necessarily in general) and perhaps best known not by his visage, but by his voice. At least, that’s how it is for me, for whom the Apollo space program was history that I had to catch up to through documentaries, etc.
Then there’s his face. Not a bad looker, but rather bland, isn’t he? There aren’t too many big name actors who have that combination of beady eyes, brachycephalic (broad) head, and thin lips… we’re talking “character actor” looks, not “romantic leading man” or even “action hero”.
If it were up to me, I’d focus as much on finding an actor who can match Armstrong’s voice and vocal patterns as much as his looks, unless the producers intend to do what the makers of Miracle did when they recycled Al Michaels’ famous call rather than use his own retread of that famous moment. Whether it’s the actor’s voice, Armstrong foleying himself, or the original recording, the emotional tension of the film will be centered on the “That’s one small step…” line. That’s gonna be a tough one to sell the public on, especially given the [still disputed] alleged flub. [The film could quickly cut from the actor saying it correctly, then to Houston [or another earthly location] to show people hearing the static-garbled version we all know, perhaps with someone saying “what the hell did he say? Did he say ‘…one small step for man’?” shortly afterwards.]
As for actors, for looks and deadpan acting I’d say maybe Liev Schrieber, but his voice (resonant and deep) is all wrong to play Armstrong. Ed Norton’s voice might be a good match, but his face is all wrong (way too dolicocephalic, distinctive, and in his own way, good-looking). Too bad Michael Moriarty is too old for the part. Maybe Matt Damon is the best overall match who’s a big name (but he couldn’t slip into any Bostonisms), but I wish they’d go with a relative unknown too, to underscore Armstrong’s reluctant acceptance about being famous. I think the screenwriter and actor Mike White is a pretty good match for looks, but he speaks in a slow Texan drawl. He’s also openly bisexual and that could prove problematic for some of the public. Maybe Breckin Meyer, who turns 34 soon? In looks he seems reasonably close (if still too cute and attractive, but a military buzz cut could go a long way to furthering a similarity), but I’m afraid his voice and personality are also too different…