The 'Always Sunny' Guys Liked the Idea of Mocking Celebrity Brands — and Wound Up Creating a Best-Selling Product of Their Own Glenn Howerton and Four Walls Whiskey CEO Casey McGrath discuss the birth of their booze and its surprisingly soulful mission.

If you created the longest-running live-action sitcom in U.S. TV history, you'd probably want to toast your success. And what better way to do it than creating your own booze to fill your glass, right?

That's what the brain trust behind It's Always Sunny in Philadelphia did. Well, not exactly, but sorta.

Rob McElhenney, Charlie Day, and Glenn Howerton are the twisted minds behind the insanely funny show (which co-stars Kaitlin Olson and Danny Devito) and they are also the founders of Four Walls Whiskey. The 80-proof Irish American Whiskey blend is smooth with a slight rye finish, making it, in this sipper's opinion, dangerously delicious. It hit shelves in the fall of last year, and is currently available for purchase in 40+ states here in the U.S., plus the in-stadium bar of Wrexham A.F.C., the soccer club that McElhenney co-owns with Ryan Reynolds.

As St. Patrick's Day partiers prepare to hit parade routes and pubs, I spoke with Glenn and Four Walls CEO Casey McGrath about the birth of the booze, how they turned the concept of a "celebrity brand money grab" on its head and the surprisingly emotional meaning behind Four Walls' name and mission.

Related: Charlie Day Says You Shouldn't Just 'Do What Makes You Happy'

What is your expert advice to revelers this St. Patrick's Day?

Glenn Howerton: If you're traditionally a Jameson drinker — a shot and a beer type of person — I'd say try it with Four Walls instead. Because we're better.

Shots fired! So how did this whole thing come together?

Casey McGrath: I worked in traditional spirits marketing for over a decade and during the pandemic, I started to see a great opportunity to build brands from scratch. And I saw that there was a lot of love and white space in the Irish whiskey category, so I gave Glenn a call. We have a lot of mutual friends and I am a massive fan of the show. He told me that they were already playing with the idea of tackling and subverting the idea of celebrity-owned brands with some sort of lager or barroom beer, so we went from there.

Glenn Howerton: I knew Casey for a long time, but I knew him as a creative director for the Kings of Leon. I didn't realize he had so much experience in the spirits market. If I'd known that maybe things would have kicked off a little bit earlier, but I do think things happen when they're supposed to happen. So once we started talking to Casey, I knew right away that the marketing side of this made sense because he got our sense of humor and understood what would feel authentic to us. And I'm a big whiskey drinker, so I got very excited about this idea instead of doing a beer. Once we realized that we could really carve something out by doing an Irish American blend and lean into the Irish American aspect of it, we just started firing on all cylinders.

Related: How Eric Church and Raj Alva Distilled Whiskey Success

How involved were you, Charlie and Rob all in landing on the flavor?

Glenn: There were a lot — a lot — of tastings. That was the best part. We had a master blender that we were working with, so everything we tried was very good. So it came down to personal preference and then testing out our personal preferences with some influential bartenders to make sure that we were on the same page. Because we knew very early on that we wanted our focus to be on the bartenders. This all started as a sort of celebration of the 15th record-breaking season of It's Always Sunny. And real bars and bartenders played such crucial roles in the building of our show that we wanted to do something to celebrate them.

How does making a whiskey brand from scratch compare with making a TV show from scratch?

Glenn: It's weird because I'm by no means a whiskey expert, but I do know what I like. And I was not a comedy expert when we started doing Always Sunny by any stretch of the imagination, but I knew what I liked. We knew what we liked. And that's this credo we've always followed: let's make something that we would watch, let's make something that we would drink. And anytime we've stayed authentic to our preferences, it's been successful.

In terms of the flavor, what is that preference you were going for?

Glenn: We were asking a lot of this whiskey. We wanted it to drink smooth like an Irish whiskey, but have the full body aspects of a rye whiskey so that it could blend in cocktails. And also, importantly, it needed to hit a $30 price point.

Casey: It's a real Swiss Army knife. It's the bartender's utility whiskey. A lot of Irish whiskey is great as a shot, but many bartenders don't use it in cocktails because it doesn't hold up flavor-wise. So we wanted something that would be the best of both worlds.

Have you thought of a way to bend the time-space continuum so that your real whiskey can wind up on the shelf of the fictional Paddy's Pub where the show is set?

Glenn: We'll have to figure something out. We have leaned into the whole celebrity spirit brand thing. We did an episode with Bryan Cranston and Aaron Paul, who make Dos Hombres Mezcal, where we were basically making fun of celebrity brands. So exactly how or if we're going to integrate Four Walls into the show, we'll see. But I mean, obviously, it is a great platform to expose fans to it.

Casey: A reminder, the name of that episode with Bryan and Aaron is "Celebrity Booze: The Ultimate Cash Grab."

How did you come up with the name Four Walls?

Casey: That's my favorite thing to talk about. It is called Four Walls in reference to the four walls of a bar. This physical space that we can all go to keep our troubles out and hold in our good times.

Glenn: Coming out of the pandemic, it was really important for us to celebrate physical spaces in a virtual world. It was time for people to get back and see each other, look each other in the eye, shake hands and give those warm hugs. I really missed that and I don't even know that I realized how much I missed it or how socially awkward I'd become. It's easy for me to get emotional about this because so much time in my formative 20s and 30s was spent in bars getting a beer and a shot and having some of the best times of my life. And that's the feeling we wanted to connect to with this.

Casey: What's funny is that Glenn and the guys are so passionate about this, but the promotion of any product can be exhausting. We're working these guys to the bone, flying them all over to events. And you'll get an exhausted Glenn that you drag kicking and screaming to another city, but then once you get him in the bar, you gotta drag him out! He never wants to leave.

Related: Why Ryan Reynolds Says "You Can't Be Good At Something Unless You're Willing To Be Bad"

Were there any runner-up names for Four Walls?

Glenn: We thought about just calling it Brown. If you watch the show, you know "brown" is very meaningful to the characters. It's what they refer to whiskey as. It's a very Philadelphia thing. But once we came up with the tagline "The Better Brown!" we realized we had a perfect marriage of both ideas.

So your Four Walls and Ryan Reynolds's Aviation Gin are offered at the Wrexham stadium. Which sells better?

Casey: Well, at the time of this interview we've only been there for three days, so, um,...we're doing better!

Glenn: It's a good question. Fair question. We'll get back to you with some numbers.