1. The story of how we all met How I Met Your Mother began when 20th Century Fox asked creators Carter Bays and Craig Thomas to pitch potential sitcom ideas. The Wesleyan alum immediately began mining stories from their post-grad days living in NYC and writing for The Late Show With David Letterman.
"I really wanted to get married," Bays reflected to Cleveland Magazine in 2008. "And as a single guy in New York, I felt that was not the normal experience."
Among the IRL tales that became plot points: When Bays invited a date to a wedding only to realize the day before he didn't have a plus-one and Thomas' brief split with college sweetheart, now-wife Rebecca Alson-Milkman.
She also took on a small role in the CBS series' creation, Thomas revealing on Reddit in 2014, "My wife cast Lily by saying 'If you're going to base a character on me, it has to be Alyson Hannigan!'"
2. Hannigan's American Pie love interest nearly dug into the role of sensitive architect Ted Mosby. "I was offered the role and it's probably my biggest regret, you know, on passing," Jason Biggs admitted on a 2021 episode of SiriusXM's The Covino and Rich Show. "I think I was in a phase of, at the time—it sounds so obnoxious to say right now—but at the time it was like, 'Okay, do I want to do TV?' I don't know that I was quite ready to go that route."
And while he knows the great moments of your life won’t necessarily be the things you do, they’ll also be the things that happen to you, it's a choice he'd definitely change.
"I'm very lucky, very fortunate. I'm still here. That's number one. Great," he added. "But yeah, if I had to pick out something I wish I had done differently, I would've taken that gig for sure."
While the part was also offered to Scott Foley, when we met Ted, he was played by Josh Radnor. According to Bays, the Columbus native was excited to learn he'd be wearing plenty of Ohio State gear.
3. Though Jennifer Love Hewitt nearly joined the party of five, ultimately she "did The Ghost Whisperer instead of HIMYM!" Thomas and Bays revealed on Reddit. Her, uh, ghosting allowed real life Canadian Cobie Smulders the opportunity to slide into Robin Scherbatsky's anchor chair.
Casting director Megan Branman "was literally flipping channels and saw Cobie just doing some bit part on, like, an hour drama," Thomas revealed. "She said from day one, 'I have your Robin,' and she was right."
4. Jim Parsons auditioned for the chance to suit up as affable playboy Barney Stintson. But he's glad his TV career took off with a big bang instead. "It all worked out fine," the Big Bang Theory lead said on a 2015 episode of Live With Kelly. The way Parsons saw it, eventual star Neil Patrick Harris was "better for the part, let's be honest."
And the Doogie Howser, M.D. star's read was pretty legen—wait for it—dary. Though he was written as "a Jack Black-type," said Thomas, Harris "came in for the audition and literally did from the pilot, the shoulder roll when he's playing laser tag."
As they watched him move furniture around before his read, added Bays, "We were sort of like, 'What's he doing?'"
The answer: Being awesome. "I did a dive roll," recounted Harris, "and I didn't judge the distance very well." Though he slammed into the wall, "Once Neil regained consciousness," joked Thomas, "we told him he had the part."
5. When it came to Lily Aldrin's Marshmallow, Minnesota-bred environmentalist Marshall Eriksen, Jason Segel was immediately ruled the first choice. "I decided that we needed someone gigantic," said Thomas, "and Jason Segel is 6-foot-4 and he could capture the truly powerful presence that I am."
Plus, added Thomas, "We're huge fans of Freaks and Geeks and we just love Jason so much. And he was our first choice for the role."
At the time, the Shrinking star was attached to another project, Segel shared, but "they waited for me."
6. Haaaaave you met Ted? Barney's go-to wingman strategy came from a move Bays' Letterman boss often used. "It wasn't even like he'd make a big thing out of it," Bays divulged on Reddit. "You'd just be hanging out in a bar with him, having a conversation, and a girl would go by, and he'd stop her and say, 'Have you met Carter?' It was very cool. And a very nice memory."
7. As for the gang's preferred watering hole, it was modeled after McGee's, a midtown pub Bays and Thomas frequented during their Letterman days.
8. The name for both McLaren's and bartender Carl was lifted from Bays' assistant Carl McLaren. "Carl's given us a lot of material," Bays joked to TV Squad. "Kinda funny how that happened.
9. While nothing good happens after 2 a.m., a lot of the top anecdotes did occur IRL. "Pretty much without fail all the best stories come from people's real lives," Bays told TV Squad, referencing the "Bachelor Party" episode where Robin gifts Lily a vibrator only to watch her open it in front of all her older relatives.
"As soon as that was pitched in the room, it was like 'OK, that's the story, that's Robin and Lily... go,'" he reflected. "And it was written within a week."
Another recurring theme that, uh, slapped, Bays revealed on Reddit, "My friend Jon Read and I used to make slap bets in high school."
10. As for that catchy earworm of a theme song, "Hey Beautiful" was written by The Solids, a band that counts Thomas as a drummer and Bays as guitarist and vocalist.
With their background, the creators had a list of tunes they wanted to work into the series, but a few suggestions came courtesy of Radnor. "He's a huge music fan," Bays shared on Reddit. "I saw Bloc Party with him at Coachella at his urging, and they ended up providing the most important music cue of the first season—the big kiss, and then Marshall on the steps."
11. Whatever you do in this life, it’s not legendary, unless your friends are there to see it. So the cast made a point "to be a functional group in some ways," Radnor detailed on CBS This Morning in 2014. "We've all done enough work and we've experienced when it's not working. But, also, when you're playing friends who really get along, you do want that to mirror on some level."
Part of that included walking into every table read as a group. The first season, shared Radnor, they'd arrive early because "Jason made the good point there's free breakfast there."
12. Producers know they were lucky to score a piece of Britney Spears in season three. Seeking them out, she landed the guest part of Abby the receptionist, drawing in more than 10 million viewers.
"By golly she put our show on the map. It can't be overstated," Bays and Thomas detailed on Reddit, noting when it came to their yearly wait to see if they'd be renewed, the pop star "rescued us from ever being on the bubble again."
13. The slew of guest stars that followed included Katie Holmes, Katy Perry, Jennifer Lopez, Mandy Moore, Enrique Iglesias and Bryan Cranston. Plus a few other familiar faces.
Harris' husband David Burtka played Lily's high school sweetheart Scooter, Hannigan's spouse Alexis Denisof reported for duty as Robin's co-anchor and onetime suitor Sandy Rivers and Smulders' husband Taran Killam took on two roles, including Goliath National Bank lawyer Gary Blauman.
One of Hannigan's daughters nearly scored a cameo as Lily and Marshall's second child, but Bays "was like, 'Nope. She’s too old,' and she got replaced," the actress told The Huffington Post. "I was like, 'You fired my child. First of all that’s ageism. I don’t think you’re allowed to fire her because she’s too old.'"
14. Smulders couldn't exactly throw every last care away when shooting the episodes that flashed back to her time as Canadian pop star Robin Sparkles.
To go to the mall, "We usually block out one extra day of shooting—only a day—to shoot a 4-minute music video with lots of sets, locations, wardrobe changes, etc, so it can be edited properly, with tons of cuts," Thomas detailed on Reddit. "Cobie Smulders winds up dancing for about 16 hours straight! Never complains."
15. Though their marriage didn't last, Harris was convinced that Barney and Robin would be awesome together.
"I'd try to do little things in our scenes together," he revealed to The Fan Carpet of his mission to pair them off, "where I gave her an extra look and an extra glance or would stare only at her during a whole scene just to see if anyone was noticing."
16. Before Emmy winner Cristin Milioti's first appearance as "the Mother" (a.k.a. Tracy McConnell) in the 2013 season eight finale, the New Jersey native had to find her footing in L.A.
"It's been hard to get used to the driving," she admitted on Conan in 2014. "I was almost arrested the first night 'cause they thought I was drunk."
Stone sober, she nonetheless, "failed every sobriety test," Milioti continued. "They ask you to do such ridiculous, hilarious things. So I couldn't stop laughing, and they said, ‘Do the alphabet backwards and slowly touch your nose while you're doing it'—which I couldn't do sober!"
Officers had her take not one, but two breathalyzer tests: "They thought it was broken," she recounted. "'No way, this girl is wasted.'"
17. The final scene shot in the series showed Ted meeting the girl with the yellow umbrella (i.e. his future bride) for the first time. And all the extras were "staff from How I Met Your Mother," Bays and Thomas revealed to Entertainment Weekly in 2013. "It was really fun. I kind of felt bad for Cristin because it was really like Jesus has risen when she showed up on the set—the whole crew was like 'Here she is, the women we’ve been waiting for for 10 years!' And she’s like, 'I’m just an actor.'"
18. Had the show not reached its final station, so to speak, creators had whipped up a backup plan involving Victoria (Ashley Williams), the baker Ted was quite sweet on when they met at the end of the first season.
"Early on, I wanted Victoria to be the mom," Hannigan told The Huffington Post. "I guess Carter later said had we got canceled she would've been the mom."
19. Speaking of just desserts, Thomas and Bays still stand by that ending despite the uproar from fans upset that they waited years to meet the mother only to—spoiler alert!—watch Ted end up with Robin when his wife died.
"If you didn't like the finale, I guess that happens," Bays wrote on Twitter at the time. "We tried something and it didn't connect with you. I hope we're still friends."
Echoed Thomas, "The fact that we have been a TV sitcom that has received this much passion from fans, for 9 years (not just tonight)—thank you."
20. Hannigan has a theory about why the last episode left viewers feeling like they'd just got slapped.
"The table read for the finale was so good, so right, but it was also like 14 hours long," she revealed. "So when I actually saw the final version of the show, I was like ‘they cut out everything!'"
All the edits left fans with a hot red burnin' on the side of their face.
"There was a funeral scene," Hannigan shared, "and all this stuff that I think the audience needed. They needed that time to process that information, instead of having it slap them in the face."
Radnor erected a similar case, citing an unaired diner scene between Ted and Robin. "I understand why they cut it," he acknowledged, "but I thought it laid in that Robin had been thinking about Ted all these years more than Ted had been thinking about Robin."
21. In another world, though, Ted is still cuddling up with the mother of his children. "16 days ago today we were in the HIMYM edit room, trying to decide between two very different endings," Bays tweeted after the divisive finale. "We only shot one script, but through edit room magic we had two possible outcomes for the series. We chose the ending we chose and we stand by it. But we loved the other version too."
Curious fans can take a peek into that alternate universe in a bonus feature on the complete series DVD collection.
22. Even if you know how something’s gonna end, that doesn’t mean you can’t enjoy the ride. And Radnor was all in, despite being told early on that he would eventually lose the mother.
"They had mentioned to me the twist about the mother in the first season, and I kind of put it out of my head," he told Vulture after the 2014 finale. "I didn't know if they would actually want to come back to it and do that, especially after Cristin, because she was so wonderful and the fans seemed to really take to her. So I asked them 'Are you guys still doing that?' And they said yeah."
Meanwhile, Milioti was gift-wrapped that storyline at the cast and crew's Christmas party. While chatting with Thomas, "He was like, 'Do you want to know how it ends?'" she told reporters at the 2014 Summer TCA Press Tour. "And as complete joke I said, 'What, do I die?' And he was like, 'Do you want to know?' and I said, 'Yeah, I do.' And he told me."
The news didn't exactly leave her feeling jolly.
"I sat there sobbing," she recounted. "He wrote me an e-mail the next day, being like, 'I'm so sorry I told you that way, you seemed really upset.'"
23. Among those that had years to process the news: Lyndsy Fonseca and David Henrie, who played Ted's grown children. As their scenes were meant to be part of one long day, they were filmed back in season one.
"Everyone abandoned the stage," Henrie told TV Line of the moment that required them both to sign non-disclosure agreeements, "and it was just me, Lyndsy and the two show creators."
Echoed Fonseca, "They also didn't know how many years the show was going to go. They filmed the ending of the show then just to have it."
24. While Ted grabbed hold of his destiny, Radnor left the series with the blue French horn his character gave Robin. Meanwhile, Smulders took home Robin Sparkles' denim jacket, Harris claimed the gang's booth at MacLaren's and Barney's playbook, Hannigan lifted a red British phone booth and Bays relocated the famed apartment swords to his own house.