This speaker is less of a main character and more of a universal voice (kind of like Yoda-speak, remember?). As mentioned in the "Detailed Summary," we're not given any specific details about who he is or where he comes from (or if he's even a "he"). This allows us to focus on the conscious action taking place, or the journey through life, instead of who's at the wheel. The speaker dominates the text, however, with all but two lines being in first person, making the poem personal yet global in its reach. Because he's an "everyman," we can easily put ourselves in his shoes and read the poem as a blanket script concerning the human condition.
We might not know where he's from (or if his name's Joe, or Luis, or Margaret), but the content of the poem gives us plenty of insight about his thought process (or how he operates) and his priorities in life. The poem illuminates the speaker's principled nature, his determination to move forward, and his reliance on metaphysical answers to life's challenges. These seem to be attributes that Kunitz holds in high regard and wants to communicate to his audience.
What also know that the speaker's had one heck of a long life and he's fit for further travel (at least he's got the mental fortitude and gumption for it).