Patriarch of the Creighton clan, Matt is a stand up guy, respected by both his family and the community. (And Shmoop—we think he's pretty swell, too.) His first act of awesome is established early on when we're told how he protected his daughter's killer from an angry community mob. That's right—he stops men from going after the guy who killed his daughter Mary. That's definitely a mold-breaking move, and one of integrity.
Matt also shows that he's not like all the other men when he weeps while his barn is getting burnt to the ground. Thanks to Jethro telling us how shameful it is to cry and hiding when he himself does (3.66), we understand that shedding a tear or two isn't really expected from manly men. Maybe it wouldn't be a big deal if it were an isolated incident, but it's not, and Matt also "has something in his eyes" when exclaiming how much he bro-loves Lincoln (11.25). Feelings are clearly not something that Matt Creighton thinks he should hide.
But his compassion is nothing new to us. His heart aches with the idea of war and thinks a country separated is "jest two weakened, puny pieces, each needin' the other" (2.11)—kind of like how the Creighton family is weakened when Bill runs off to the Confederacy.
Though strong in spirit, Matt deteriorates a bit physically after he suffers a heart attack. Between the stress of war, Bill leaving for the South, Jethro and the Creighton family getting bullied, and all the farm work, Matt's ticker has been carrying a heavy load. It doesn't seem surprising that the man who is a model for compassion literally ends up with a broken heart.