The actor, who also directed the episode “Heart and Soul,” offers insights into key scenes.
“Heart and Soul” contained its fair share of strain and pain as well.
“It blew my brain wide open.

Chris Sullivan, Chrissy Metz, and Mandy Moore on ‘This Is Us’.Ron Batzdorff/NBC (3)
But it also switched tones and tackled some serious parenting moments.
In your eyes, what was the biggest challenge in bringing that to life?
While always staying grounded.
It was a delicate balance, and I think we’ve managed to strike it.
How did that factor into your presentation of these scenes?
But you know, Randall and Rebecca can almost do no wrong.
[Laughs] It actually gives them some freedom to really swing for the fences.
It gives them opportunities for big moments, because the audience is with them.
To be clear, you’re saying Americakind oflikes Mandy Moore and Sterling K. Brown?
I’m saying they like them more than me and Jon Huertas.
Rebecca loses her cool and slaps Kate after Kate calls her a “slut.”
Take us behind the filming of that moment with Mandy and Hannah.
The third challenge is to earn it.
Yeah, but there’s part of me that totally gets it, you know?
Especially having spent so much time with Randall the character.
And, of course, the day involving the Big Green Egg looms large…
The Big Green Egg is a symbol of a day where we arrive at that crossroads.
But it’s possible for you to’t arrive at that crossroads without taking a thousand single steps.
Everything you’re seeing now are these steps towards that inevitability.
How conflicted is Toby by this long-distance arrangement?
It’s very complicated and it’s very tricky and it’s very hard to do.
But Toby’s loving it.
Aside from being apart from his family, he is appreciated.
He loves his job, people at his job appreciate him.
The obvious worst part is that he has to be away from his family so much.
I think maybe the solution is just one more gift?
People don’t realize that.
It’s usually just one more present.
How would you describe that episode?
Sometimes people are just trying so hard to get a round peg into a square hole.
What can you say about what will boil over in that episode?
How about this: When the smoke clears, the line will have been drawn.
You and Chrissy have said that you didn’t discuss the impending split because it was too sad.
Now that we’re moving closer to these pivotal episodes, have you talked more to her about it?
And have you talked to Chris Geere about it?
Which is exciting for everybody.
Miguel’s never been so happy to see a new character.
I gotta tell you, that was one of the most fun days of shooting.
And every take, he gave me something completely different, a different line.
It’s a really great way to cap off that scene.
That is the moment that he realizes.
I don’t think he has considered any serious feeling until that moment.
Do you remember talking to John about different ways to play that?
I don’t think I had to.
I don’t think we talked about it that day.
Jon is a master at what he does.
And just in that look, you’re free to see the beginnings of everything.
[Deadpan] We directed it.
It wasn’t in the script, but Griffin insisted.
So I had notes and it was very well lit, very well shot, very tasteful.
But yeah, it didn’t make the episode, unfortunately…
It was an honor to direct this entire cast, but Griffin Dunne is a legend.
And a hero of mine.
So to even be in the same room with him, acting, directing, I’ll do whatever.
I’ll do whatever he wants.
I would drive Griffin Dunne’s Uber.
What are you most looking forward to tackling in the back half of this final season?