Cobra Kai's Jacob Bertrand on Hawk's big win — and why you should NEVER ask him for spoilers

Warning: This article contains spoilers for Cobra Kai season 4.

From victim to bully to All Valley karate champ — it's been quite a character trajectory for Cobra Kai's Eli "Hawk" Moskowitz (Jacob Bertrand). After going fully over to the dark side in season 3 — and even breaking the arm of his best friend, Demetri (Gianni DeCenzo) — this season Hawk atoned for his awful behavior while training with Miyagi-Do's Daniel LaRusso (Ralph Macchio) and Eagle Fang sensei Johnny Lawrence (William Zabka).

Though Hawk ended season 4 (now streaming on Netflix) as the All Valley boys' karate champion, his path to victory featured some heartache — and a forcible de-hawking haircut at the hands of his former Cobra Kai buddies. Bertrand — who will voice the Batmobile in the upcoming animated series, Batwheels — talks to EW about Hawk's big win, adjusting to life without a mohawk, and the origins of his character's hilarious back-tattoo flex maneuver.

ENTERTAINMENT WEEKLY: How did you find out that Hawk was going to win the boys' tournament?

JACOB BERTRAND: No one knew for a really long time. Like, most people didn't know until episode 10 actually came out who was winning for the girls' and the boys' divisions. But when I was sitting down about to film the scene where I walk in and my hair is all messed up and shaved, the big three were in the room and they were giving Miss Vanessa, our hairdresser, exact details of what they wanted my messed-up hair to look like. And they told me, "Hey, we're not doing this for nothing. You're gonna be an All Valley champ." They told me in the hair room right there and I was like, "Oh dang, that's crazy!"

Going back to season 3 for a minute, what do you think it was that caused Hawk to get caught up so much in the Cobra Kai mentality that he broke his best friend's arm?

Well, he wasn't around Miguel [Xolo Maridueña] and Demetri and Johnny, and I think those three people are people who really have the best intentions for him. Who was around him was Tory [Peyton List], who's a fricking maniac, and then Kreese [Martin Kove], who is an even bigger maniac. I think being under the influence of Kreese would change anybody — you either run or you buy into it and turn out like Hawk.

Also at that time, Hawk was sort of given all this power and his newfound confidence, and he didn't really know which direction to point it. I just think he was very impressionable at that point and was just very easily influenced. And now that he is back on the good side and back with his binary bro, and Daniel and Johnny, I think they're definitely going to keep him on the good side.

Let's discuss the mohawk. Was it your real hair?

It is my hair! Yeah. Actually, season 4 was the only season that it wasn't all my hair. In season 4 I had an extension in. I had black roots and my hair was dyed red, and then I had a little extension in. My mohawk was maybe like five or six inches, and then final mohawk when they put the extension in, it was like eight or nine inches [high]. But at the end of season 3, when I have a mohawk, I actually had an eight-inch mohawk that was all my real hair.

How long did it take to get spiked up when it was time to shoot?

It takes about an hour to get up and running — an hour, and maybe like two bottles of hairspray.

For the finale, was it strange fighting without the mohawk? Did it affect your center of gravity or anything?

What's funny is I genuinely did feel a difference when I would fight. All the different head moves you have to do, I'm so used to doing it with eight inches of rock-solid hair on top of my head. Doing it without it, I definitely felt very light, and it was very peculiar to have to move around without a mohawk. And I also felt like I'd lost a little bit of confidence. Walking around on set and you got this huge mohawk, I feel like just subconsciously I'm like, "Yeah, you know, I'm like 6'5" with this mohawk." And then it's gone and you're like, "Aw damn, I'm back down to being like 5'8", 5'9." This is a bummer."

There's that wonderful moment in episode 9 when Moon [Hannah Kepple] comes and gives Eli a pep talk — and a kiss — right after Kyler [Joe Seo] the bully calls him "Lip." How do you think that ultimately factored into his victory?

I think that gave him the confidence he needed. I think he was just so in his head about what he looked like and how people are judging him. He sort of reverted back to that Eli mentality of "I'm not enough. Everyone's making fun of me." Just everything you tell yourself when you're a kid getting bullied. I think having someone like Moon, who he used to date and is still very much in love with, telling him, "You are enough, you've always been enough, and you're going to be no matter what the outcome is," I think that was like the fire he needed. And he's like, "I'm gonna win this whole f---ing thing!"

There was a lot of great response from fans to that "I'm gonna win this whole f---ing thing" moment. What's it been like to see the fan reaction to Hawk's win?

It's pretty cool. I love that moment because we only get a certain amount of F-bombs each season, and I was happy that I got it. I think I've gotten two so far — two of the four have been mine. I guess I have the edgiest, coolest character. One thing I thought was funny about that moment is we did an alt take where I didn't say the F-bomb, because they thought it was weird that Eli comes up to Mr. LaRusso and is like, "I'm gonna win this whole f---ing thing, Mr. LaRusso!" Like, right into Daniel LaRusso's face.

They made the right choice going with the F-bomb take.

Well, you know what, I think I just say the F-word so well that I think they thought it would be a crime for it to not make it in there. They're like, "You know what? He's just so cool. Like we just, we just can't take this away!" That's what I heard all of the editors say, at least. [Laughs]

Eli and Moon's kiss happens in front of a big crowd. What was that like to film?

Yeah, there actually was a pretty large crowd. It was weird. I mean, I don't know, I haven't done a lot of kissing [on screen], so I still am like trying to feel it out and get, you know, 100 percent comfortable with it… It still feels weird to me to be kissing, like, a random person who is not a significant other. I'm not a pro yet.

Of course there's that amazing over-the-top moment in the finals where Robby [Tanner Buchanan] rips off his gi, prompting Eli to rip his off as well. What was your reaction when you first learned about the shirtless showdown?

I first heard about it when Tanner told me. Tanner was like, "Yo, so for the final fight you and me are gonna be shirtless." And I was like, "No we're not. You're lying." And he's like, "No, dude, I'm serious! We're gonna be shirtless and we're gonna be fighting." And I was like, "Dude, no way. Why would we take our shirts off? That makes no sense." He's like, "I don't know, dude, I'm just telling you, I heard we are taking our shirts off." Then I asked the big three and they're like, "Yeah, we're debating it." Finally, the writers were like, "You guys are gonna take your shirts off." It was fun to get to do this huge fight in front of a lot of people shirtless — and to get to kick Tanner in the abs a couple times. I almost broke a toe.

How long has it taken you to master the hawk-tattoo flex, which Eli does after he takes his gi off?

In season 1 when Hawk first wins his fight and he does that back-flapping thing, that was actually a joke that I did way earlier in the season. In a different scene I had my shirt off, that I was just doing it to make Xolo laugh. The writers came up to me and they were like, "Do that! That's badass." And I was like, "I literally did this as a joke. I don't think this is gonna work." And they're like, "No, do it, do it, do it!" So I did it, and people ended up frickin' loving it because the writers, they know everything and they're always right.

So then in season 4 when I took my shirt off, I was just going to take my shirt off, throw my gi, and then turn around go to fight. And then Justin [Armer], he's the guy who's on wardrobe and he touches us up right before we [shoot], he was touching me up and he was like, "Hey, right before you turn around, do a little Hawk flourish with your back. It'll look sick if the camera's right on your back!" And I was like, "Oh, that's a good idea!" I only did that in one take. It was the last take, so all of that cool credit has to go to Justin because he is the fricking man.

The show has wrapped production on season 5, though Netflix hasn't announced when those episodes will drop. How do you handle it when fans try to get spoilers out of you?

Usually I just punch them in the face and say, "There you go. That's your spoiler. There's lots of fighting." [Laughs] Usually it's like, "Oh, I can't tell you that. Netflix is gonna hit me with a big stick if I tell you anything." I honestly usually just say that, or I just say that I die. So if you're a fan and you're reading this and you wanna ask me about spoilers, one of three things [will happen]: Either I'll make a Netflix joke, I'll make a joke that I die, or your nose will be very bruised. Those are the three options. [Laughs]

Well, you cannot punch me because we're talking on the phone, so I'm just gonna ask you what can you preview about Hawk's story line in season 5?

There's a lot of unlikely team-ups. Season 5 was a good experience. It was very fun getting to film with everyone. That's something that's different about season 5, getting to be in scenes with almost everybody.

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