For purposes of SEO, should the title tag of my blog post be the same as the post headline?

- Patrick H. 35 / M / Stow, MA

Not necessarily, unless you want to rank for the exact phrases you use as your headlines.

I’d recommend to use the title tag do target 1-2 keyphrases containing in your headline, and use your headline to employ those keyphrases in a useful sentence, providing semantic usage of both the keyphrase and context for its usage.

Thanks Ryan. Would their be any harm in using the same?

No, my recommendation is just a better practice, not a necessity. For the sake of simplicity, you can definitely use the same info for both places with no harmful outcome.