Is there a word for someone who makes sacrifices?

Pretty straightforward... I'm wondering if there's any sort of word (describing one's personality) for someone who makes sacrifices... it's not really a 'selfless' person, but rather someone who is willing to take initiative and possibly lose something of value. "Sacrificial" isn't right, and I'm not sure if such a word even exists, but "sacrifice-making" sounded kind of lame. Thoughts?