Alyson Lee Hannigan (born March 24, 1974) is an American actress and television presenter. She began her film career with supporting roles in the comedy films Impure Thoughts (1986) and My Stepmother Is an Alien (1988), receiving a Young Artist Award nomination for the latter. In 1999, she began starring in the American Pie film series as Michelle Flaherty, the films' primary love interest, appearing in every film in the series from 1999 to 2012. For her role in the series, she was nominated for three Teen Choice Awards and won a Young Hollywood Award. She went on to star in the parody film Date Movie (2006), the slasher film You Might Be the Killer (2018), and the superhero film Flora & Ulysses (2021).
Hannigan got her start in television starring in the short-lived sitcom Free Spirit from 1989 to 1990, for which she earned a Young Artist Award nomination. After several minor roles in television films and other series, she appeared in her breakout role as teenage witch Willow Rosenberg in the supernatural drama series Buffy the Vampire Slayer, appearing in every episode from 1997 to 2003. Her role on the show was critically acclaimed and won her the Saturn Award for Best Supporting Actress on Television and a Teen Choice Award. From 2005 to 2014, she starred as Lily Aldrin in the sitcom How I Met Your Mother, for which she won two People's Choice Awards. Hannigan hosted the television show (2016–2023), and provided the voice of Claire Clancy in the Disney Junior animated series Fancy Nancy (2018–2022).
Living with her mother and attending North Hollywood High School, she successfully auditioned for agents while visiting her father in Santa Barbara. After high school, she attended California State University, Northridge, where she was a member of the Alpha Chi Omega sorority and earned a degree in psychology.
In 1997, Hannigan was cast to play Willow Rosenberg, Buffy Summers' best friend, on the supernatural Television show Buffy the Vampire Slayer. The show became a success, and Hannigan gained recognition, subsequently appearing in several films aimed at teenage audiences, including Boys and Girls (2000). She had a supporting role as Michelle Flaherty in the comedy film American Pie (1999), and appeared in a much larger role in its sequels American Pie 2 (2001) and American Wedding (2003). In 2017, Forbes reported that the American Pie films have grossed $989.5 million at the worldwide box office, and became a Popular culture phenomenon.
She also had a recurring guest spot on the Buffy the Vampire Slayer spin-off, Angel, reprising her role of Willow. In early 2004, Hannigan made her West End debut, starring in a stage adaptation of When Harry Met Sally... at the Theatre Royal Haymarket, opposite Luke Perry.
In February 2006, she starred as Julia Jones in Date Movie, a parody of Romantic comedy. She was also a guest star on the ABC animated sitcom The Goode Family in 2009.
Hannigan joined forces with Emily Deschanel, Jaime King, Minka Kelly, and Katharine McPhee in a "video Sleepover" featured on FunnyOrDie to promote regular breast cancer screenings for the organization Stand Up 2 Cancer. Hannigan reprised the role of Michelle in the comedy film American Reunion (2012). The film followed the friends attending a high school reunion thirteen years after graduating from high school. The film was a success at the box office, and grossed $235 million worldwide. For her role in the film, she was nominated for award at the 2012 Teen Choice Awards.
In September 2023, Hannigan was announced as one of the contestants on season 32 of Dancing with the Stars, partnering with Sasha Farber. The couple made it to the finals and finished in fifth place.
| 1986 | Impure Thoughts | Patty Stubbs | Credited as Allison Hannigan |
| 1988 | My Stepmother Is an Alien | Jessie Mills | |
| 1998 | Dead Man on Campus | Lucy | |
| 1999 | Hayley Wagner, Star | Jenna Jakes | |
| American Pie | Michelle Flaherty | ||
| 2000 | Boys and Girls | Betty | |
| 2001 | Beyond the City Limits | Lexi | |
| American Pie 2 | Michelle Flaherty | ||
| 2003 | American Wedding | ||
| 2006 | Date Movie | Julia Jones | |
| Farce of the Penguins | Hottie Penguin | Voice | |
| 2011 | Love, Wedding, Marriage | Courtney | |
| 2012 | American Reunion | Michelle Levenstein | |
| 2016 | Do You Take This Man | Rachael | |
| 2018 | You Might Be the Killer | Chuck | |
| 2021 | Flora & Ulysses | Phyllis Buckman | |
| 2026 | Meghan | Post-production |
| 1989–1990 | Free Spirit | Jessie Harper | Main role, 14 episodes |
| 1990 | Roseanne | Jan | Episode: "Like, a New Job" |
| 1991 | Switched at Birth | Gina Twigg (Age 13–16) | Television film |
| 1993 | Almost Home | Samantha | 2 episodes |
| 1994 | Touched by an Angel | Cassie Peters | Episode: "Cassie's Choice" |
| 1995 | The Stranger Beside Me | Dana | Television film |
| 1996 | For My Daughter's Honor | Kelly | Television film |
| Picket Fences | Peggy Patterson | Episode: "To Forgive Is Divine" | |
| 1997–2003 | Buffy the Vampire Slayer | Willow Rosenberg | Main role, 144 episodes |
| 1999–2000 | 100 Deeds for Eddie McDowd | Gigi | Voice, 3 episodes |
| 2000 | The Wild Thornberrys | Gerda | Voice, episode: "Every Little Bit Alps" |
| 2001–2003 | Angel | Willow Rosenberg | 3 episodes |
| 2002–2003 | Rugrats | Cynthia P.I./Young Starlet | Voice, 3 episodes |
| 2004 | That '70s Show | Suzy Simpson | 2 episodes |
| King of the Hill | Stacey Gibson | Voice, episode: "Talking Shop" | |
| 2005 | Veronica Mars | Trina Echolls | 3 episodes |
| 2005–2014 | How I Met Your Mother | Lily Aldrin | Main role, 206 episodes |
| 2009 | The Goode Family | Michelle | Voice, episode: "Graffiti in Greenville" |
| 2010 | Food Network Challenge | Herself | Host; Episode: "Outrageous Pumpkins 2" |
| 2011 | The Simpsons | Melody | Voice, episode: "Flaming Moe" |
| 2011, 2018 | Robot Chicken | Various voices | 2 episodes |
| 2011; 2013; 2023 | American Dad! | Chelsea | Voice, episode: "Virtual In-Stanity" |
| Ugly Stepsister #2 | Voice, episode: "Finger Lenting Good" | ||
| Lexie | Voice, episode: "Cow I Met Your Moo-ther" | ||
| 2014 | Sofia the First | Winter | Voice, episode: "Winter's Gift" |
| The McCarthys | Pam | Episode: "Red Sox Swap" | |
| 2016–2023 | Herself | Host, 103 episodes | |
| 2018–2022 | Fancy Nancy | Claire Clancy | Voice, main role (57 episodes) |
| 2019 | Kim Possible | Ann Possible | Television film |
| Pure | Esther Dunkel | 2 episodes | |
| Mary Stauffer | Television film | ||
| 2020–2021 | Outrageous Pumpkins | Herself | Host, 8 episodes |
| 2020 | Girl Scout Cookie Championship | Host, 4 episodes | |
| Outmatched | Annabeth | Episode: "Couple's Friends" | |
| 2021 | Martha Gets Down and Dirty | Herself | Episode: "House Planting Party" |
| Adorableness | Panelist | ||
| 2023 | Doogie Kameāloha, M.D. | Dawn | Episode: "Message from the Chief" |
| Office Race | Pat | Comedy Central original television film | |
| Dancing with the Stars | Contestant | Contestant on season 32; 11 episodes | |
| 2024 | Beat Bobby Flay | Episode: "Sweet Defeat" |
| 2004 | When Harry Met Sally... | Sally Albright | Theatre Royal Haymarket |
| 1989 | Young Artist Award | Best Young Actress in a Motion Picture – Comedy or Fantasy | My Stepmother Is an Alien | |
| 1990 | Best Young Actress Starring in a Television Series | Free Spirit | ||
| 2000 | Young Hollywood Awards | Best Ensemble Cast | American Pie | |
| Teen Choice Awards | Choice TV Sidekick | Buffy the Vampire Slayer | ||
| 2001 | Saturn Awards | Best Supporting Actress on Television | ||
| Teen Choice Awards | Choice TV Sidekick | |||
| 2002 | Saturn Awards | Best Supporting Actress on Television | ||
| Teen Choice Awards | Choice TV Sidekick | |||
| 2003 | Saturn Awards | Best Supporting Actress on Television | ||
| Satellite Awards | Best Supporting Actress – Television Series | |||
| Teen Choice Awards | Choice TV Sidekick | |||
| 2004 | Choice Movie Actress – Comedy | American Wedding | ||
| Choice Movie Liplock (shared with Jason Biggs) | ||||
| 2008 | Choice TV Show – Comedy | How I Met Your Mother | ||
| 2009 | People's Choice Awards | Favorite TV Comedy Actress | ||
| 2010 | Favorite TV Comedy Actress | |||
| 2012 | Teen Choice Awards | Movie Actress – Comedy Comedy | American Reunion | |
| 2014 | People's Choice Awards | Favorite TV Gal Pals | How I Met Your Mother | |
|
|