It's widely known that Cummings wrote this poem as an elegy to his father, Edward Cummings, who died in a car accident. But it's hardly ever a good idea to think of the author as the speaker in a poem, since authors like to embellish and push past themselves even when writing about very personal subjects. So, we're just going to assume that our speaker is some unnamed son who's grieving for his dad.
So what do we know about this guy? Well, one thing is obvious: he really has a lot of respect for his father. He makes his father seem like the absolute man in this poem, claiming that his dad inspired people wherever he went, was bursting with generosity, and made a point of challenging conformity throughout his life. The fact that the speaker thought these things made his dad cool tells us that he thinks these things are cool too. We're guessing that our speaker was a guy who "lived his soul" just the way that his father did (67).