Grew up in Allentown, Pennsylvania.
Has appeared on the cover of three Francine Pascal books.
Put attending college on hold (this was to be Fordham University in New York) to film Mean Girls (2004).
Was considered for the roles of Regina and Cady in Mean Girls (2004). These roles eventually went to Rachel McAdams and Lindsay Lohan, respectively.
She began modeling at age 11.
Good friends with American Gun (2005) co-star Nikki Reed.
The correct pronunciation of her last name is "Sigh-Frid".
In May 2008, she dressed up as Alice of "Alice in Wonderland" for a seven-page spread for Vogue Italia. That same month, she was also featured in the promotional poster for her movie musical Mamma Mia! (2008).
Originally auditioned for the title role on Veronica Mars (2004) but lost the role to Kristen Bell. Instead of playing Veronica Mars, she was offered the role of Lilly Kane, Veronica's dead best friend. She was so popular in this role that she was brought back more often than ever expected.
As a child model, she initially signed with Image International Agency in Allentown, Pennsylvania before working under Bethlehem's Pro Model Agency and eventually with Wilhelmina agency in New York.
Attended and graduated from William Allen High School in Allentown, Pennsylvania (2003).
Missed 70 school days during her senior year in high school due to her acting commitments.
If she were not into acting, she would have liked to study meteorology. She admits being fascinated by weather.
Trained in classical opera for two years and studied under a Broadway voice coach for almost five years.
While living in Allentown, Pennsylvania, she got to see musicals in Manhattan such as "Cats" and "Les Miserables", which is her all-time favorite musical.
Her special skills and interests include dancing, singing, painting and tennis.
Beat several actresses for the role of Sophie Sheridan in the film Mamma Mia! (2008). One of the actresses was fellow co-star Rachel McAdams who acted alongside Seyfried in the film Mean Girls (2004). In this film, McAdams beat Seyfried for the role of Regina George.
Auditioned for the lead role of Kelli Presley for the horror remake Black Christmas (2006), but lost out to Katie Cassidy.
Was in a relationship with Dominic Cooper, having met on the set of Mamma Mia! (2008) (October 2007-May 2010).
Lost the role of Babydoll in Sucker Punch (2011) because she was committed to her HBO series Big Love (2006).
Named one of People magazine's 100 Most Beautiful People in the World (2009).
Wanted to be an actress at age 10 after watching Romeo + Juliet (1996) with her father, who was a film buff.
Has an Australian shepherd dog named Finn who has his own Twitter account.
She has German, with smaller amounts (to varying degrees) of English, Scottish, Welsh, Swiss-German, and Scots-Irish/Northern Irish, ancestry.
Was considered for the role of Daisy Buchanan in The Great Gatsby (2013), but Carey Mulligan was cast instead.
Was in a relationship with Ryan Phillippe (October 2010-May 2011).
Her role in the drama film Nine Lives (2005) was written specifically for her.
One of the songs on the Dear John (2010) soundtrack was written by her.
Named one of People magazine's 100 Most Beautiful People in the World (2010).
Ranked #2 in Who magazine's "Most Beautiful People" in 2010.
Ranked #59 in the 2011 FHM Australia list of "100 Sexiest Women in the World".
Ranked #1 on People magazine's "25 Beauties (and Hotties) at 25" list in 2011.
Ranked #92 on Ask men's top 99 "most desirable" women on 2012 list.
Ranked #3 in Glamour magazine's "50 Most Glamorous Women of 2010" and was also named "The Most Down-to-Earth".
Ranked #17 in Glamour magazine's "30 Hottest and Sexiest Stars Under 30" (2010).
Ranked #4 in People magazine's Most Beautiful 2009 - Beautiful at Every Age.
She was ranked as having one of the "Most Beautiful Famous Faces" for six consecutive years on the list of "The Annual Independent Critics List of the 100 Most Beautiful Famous Faces From Around the World". She was ranked #32 in 2005, #23 in 2006, #46 in 2007, #65 in 2008, #5 in 2009 and #9 in 2010.
Her father, Jack is a pharmacist, while her mother, Ann, is an occupational therapist.
Ranked #41 on Ask men's top 99 "most desirable" women of 2012 list.
Named as having the "Sexiest lips" by Victoria's Secret What Is Sexy list (2012).
Admitted to David Letterman that she gets nervous doing television interviews and often fortifies herself with a drink beforehand, usually whiskey.
Has struggled with anxiety disorder and panic attacks.
Had a body double for her shower scene in the mystery thriller Gone (2012).
Very good friends with Gone (2012) co-star Jennifer Carpenter.
Previously in a relationship with actor Justin Long from October 2013 to September 2015.
Auditioned for the role of Alexandra King in The Descendants (2011), but was beaten out by Shailene Woodley.
Distant cousin of Gwyneth Paltrow and Gwyneth's mother Blythe Danner, through their common descent of the Danner family (a Pennsylvania Dutch [German] family).
(March 12, 2017) Married her boyfriend of a year Thomas Sadoski following a 6-month-long engagement.
Gave birth to her 1st child at age 31, a daughter Nina Sadoski Seyfried on March 21, 2017. Child's father is her husband, Thomas Sadoski.
Was 8 months pregnant with her daughter Nina when she completed filming on First Reformed (2017).
(December 2, 2016) During an interview with W magazine, she unintentionally revealed she and her husband (then fiancé) Thomas Sadoski were expecting a son.
Is the second of the four main Mean Girls (2004) cast members to get married and have a baby; the first being Lacey Chabert.
Returned to work 2 months after giving birth to her daughter Nina to begin filming Gringo (2018).
Her daughter weighed 3.005321 kilos or 6 LBs 10 Oz at birth early in the morning of March 21st she revealed that in a appearance on Dr Elliot Berlin's informed pregnancy and parenting podcast seven weeks after her daughter was born in which she also said at that point the baby weighed 4.535950 kilos or 10 LBs and also that she'd be back on the show in August to update.
Gave birth to her daughter Nina five weeks after her close friend Amber Tamblyn gave birth to her daughter Marlowe.