Alyson Hannigan has been working in film and television since the age of four when she first started appearing in commercials. Hannigan booked her first big job when she was eleven years old and her career has steadily climbed ever since.

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Hannigan is most recognized for playing the role of Willow Rosenberg in the hit teen television series, Buffy the Vampire Slayer, and more recently for her work on the comedy series, How I Met Your Mother. In the many decades that Alyson Hannigan has been in the entertainment industry, she has had her fair share of flops and successes.

Date Movie (7%)

Alyson Hannigan stars as Julia Jones in this parody feature film about a couple planning their wedding. The film parodies popular movies like My Best Friend's Wedding, Meet the Parents, and Shallow Hal. 

Date Movie was not received well by critics who couldn't appreciate the toilet human and empty pop culture references. It did, however, do very well amongst audiences and at the box office, raking in over $80 million.

My Stepmother Is An Alien (19%)

My Stepmother is an Alien cast

In this 80's sci-fi comedy, a very young Alyson Hannigan plays Jessie, who is the daughter of Dan Aykroyd's character, Steven. Steven falls in love with Celeste, played by Kim Basinger.

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Celeste is an extraterrestrial who comes to earth on a mission but loses sight of it when she falls in love with Steven and experiences true intimacy. A young Seth Green also stars in this film. Green and Hannigan will go on to work together on the hit series, Buffy.

American Reunion (45%)

In the fourth installment of the American Pie franchise, everyone's favorite characters come back for their high school reunion. It's also a reunion for fans of the franchise and there's a nostalgic feeling throughout the film.

Alyson Hannigan returns to reprise her role as band geek turned wife of Jim, Michelle. The film did not gain a lot of positive reviews from critics, but did very well at the box office, grossing $250 million.

American Pie 2 (52%)

Michelle and Jim sitting together in American Pie 2

In the sequel to the first film in the franchise by the same name, American Pie 2 reunites Jim, Oz, Finch, and Stifler as they return home for summer break after their freshman year of college. The boys rents a beach house and Jim thinks he's finally ready to sleep with his crush, Nadia.

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At the same time, Jim finds himself spending more time with band geek Michelle, ultimately falling for her. Michelle feels the same and fans finally see the couple they have been rooting for, together.

American Wedding (54%)

Originally the third installment of the American Pie franchise was also supposed to be the final. In the third film, nine years after the previous sequel was released, it's Jim and Michelle's wedding day; however, that doesn't stop the chaos and the debauchery these films are known for, especially considering American Wedding features Stifler the most prominently.

After a lot of close calls, Jim and Michelle do manage to make it down the aisle to say their "I-dos."

American Pie (61%)

Before this film, Alyson Hannigan was considered a quirky best-friend type when it came to casting her in film and television. Initially, the role of Michelle in American Pie seems like it is just that. Michelle is sweet and quirky, and a bit of a band geek.

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As Jim and the audience get to know Michelle, they realize that you should never judge a book by its cover. Michelle is full of surprises and Alyson Hannigan's comedic timing with the character creates some classic movie moments.

Buffy The Vampire Slayer (82%)

Buffy the Vampire Slayer became one of the most nostalgic and successful shows of the late '90s and early 2000s. Originally, the role of Willow Rosenberg, best friend to Buffy and Xander, was played by another actress, but after the pilot was shot and aired for the network, the role was recast and Alyson Hannigan won the part.

Playing Willow Rosenberg made Alyson Hannigan a household name and launched her into a new level of stardom in the entertainment industry.

How I Met Your Mother (83%)

Lily Aldrin frowning in How I Met Your Mother.

After Buffy's successful seven-season run, Alyson went on to star in another hit television series, How I Met Your Mother, as Lily Aldrin. This series ran for nine successful seasons on the CBS network and gave Hannigan a chance to really stretch her comedic muscles throughout her run on the show.

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The show's creator, Craig Thomas, said he based Hannigan's character on his wife, who was excited when she learned Hannigan would be playing the role because she was such a big fan of Buffy.

Angel (88%)

In the spin-off to Buffy, Alyson Hannigan reprises her role as Willow Rosenberg in a few episodes of Angel. In fact, one of Willow's best moments in either series happens in Angel. At the end of season 5 of Buffy, the slayer is killed in her final battle against Glory, taking her own life to save her sister's.

Willow is the one who goes to Los Angeles to tell Angel the terrible news. At the end of season 2 of Angel, Angel and his gang find Willow waiting for them to deliver the news and they know that by the look on her face, what she is about to say is awful.

Veronica Mars (92%)

In between her successes as a series regular on Buffy the Vampire Slayer and How I Met Your Mother, Hannigan filmed three episodes of the hit series Veronica Mars, starring Kristen Bell.

Hannigan plays Trina Echolls, sister to Logan, played by Jason Dohring, and daughter to Aaron, played by Harry Hamlin.

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