Like Kinjirou(Mayo Chiki), Rin(Shuffle!), or Toyoma(Clannad). Shit even Minato(Sekirei).
Kinjirou is really pretty dedicated to making sure that Konoe is happy etc, regardless of the fact that he's got gynophobia. Anytime she's upset he runs after her, and even holds her close. Strongly proclaiming that he's there for her even with his condition. I like that sort of dedication.
Rin does the same for pretty much every girl. Anytime they're upset or struggling he always helps, and often it puts him at risk or in the wrong and he just takes the fall for them because he cares. I mean, what he does for Kaede is absolutely incredible. That was absolutely selfless. Shuffle! was the first anime where I actually liked the male protag. It felt like he deserved those girls loving him. He did great things for each of them, rather than just being some random cute guy who was shy etc. Rin is a normal guy, and he's selfless as fuck.
Despite being a "troublemaker", Toyoma is a great guy and does whatever he can to help the girls around him, regardless of whether he wants to or not.
While the final dude, Minato is kinda shy at times, it's usually because his Sekirei are sex personified. rofl. But he goes out of his way and even risks his own life to save and keep them all happy.
They're all pretty different characters, yeah, but all four of them try their best to keep all the girls around them happy. They help every time they can, and they're not all timid and annoying. Anyone know anymore who are like that? Trying to find some more romance/harem shows that have a main dude who is selfless and has like... absolute determination to help the one he cares for, etc.
Prefer guys in harems that have some mix of comedy and drama/serious tone. Kinda like, well... the four anime these guys are in!
I know this is a strange request, but since the bit of searching I've done is giving me things more like... "Oh, he's like this guy because he's scared of girls. Or this guy because they both have glasses." I figure you guys would be best to ask.
e: Also; Seen SAO and Kirito kinda fits this too. Absolute determination.