What are the challenges of playing a variation of the same character?

There were logistical and technical challenges and long days. Waa waa waa! I try not to complain too much about how hard my fabulous show business job is. The good news was that Justin and I had a lot of time to figure out how to differentiate these characters — and what not to do. I considered all kinds of subtle things in terms of appearance that ultimately seemed unnecessary because the more interesting thing was how has a person really changed at his core in the second 30 years of his life due to his environment, his experiences.

Which Howard is the dominant scene partner?

In general, we preferred shooting the kinder, gentler Howard first. For the first 20 pages of the script, I was thinking, this is the character that I’ll play, this is our protagonist, and this is the guy that I’m identifying with. And when I got to the scene where we meet Howard from the Other Side and the two worlds are revealed, I was as surprised as I wish audiences could be.

T: The New York Times Style Magazine recently included you in a roundup of outstanding character actors. Do you consider yourself one?

Absolutely. My standard joke is that character actors are just actors who are not particularly good-looking. I think the public perception is there’s your leading man, your Clooney and your Pitt, and then there’s the other guys. The vast majority of actors that I have worked with like to think of themselves as character actors. To me, putting the word character in front of the word actor is a compliment because it means people are seeing the character rather than the actor, which at the end of the day is my ultimate goal.

How did life change after your Oscar for best supporting actor for playing the tyrannical music instructor Terence Fletcher in “Whiplash”?