On her role in the movie, she stated during an interview with Entertainment Weekly, "Simply Irresistible was [just] a bad choice—and for that it was a great learning experience. Gellar was cast in the leading role of a mobster's daughter in James Toback's independent drama Harvard Man, but some pointed out the sexual nature of her character, comparing it with that of Kathryn Merteuil in Cruel Intentions; Variety remarked that Gellar was "fun to watch in the adorable, devious bitch mode she test-drove" in her portrayal of Kathryn, and similarly, DVD Talk wrote that Gellar's "self-serving Mafia Maiden echoes her bitchy turn" in the 1999 film.
Gellar then appeared as Daphne Blake in the live action–comedy Scooby-Doo, directed by Raja Gosnell and co-starring Freddie Prinze, Jr., Linda Cardellini and Matthew Lillard. reuniting after a two-year disbandment to investigate a popular horror resort in a remote island.
The series ran for one season and earned Gellar two Young Artist Award nominations, for Best Young Actress in a New Television Series and for Best Young Actress in an Off-Primetime Series.
At the audition, Gellar read both her own lines and those of Harper, impressing the directors enough to cast her in the role.
The miniseries won the Emmy Award for Outstanding Limited Series.
She next took on the leading role in the 1992 syndicated teen serial Swans Crossing, which chronicled the lives of a group of wealthy teenagers.
She screen tested several times originally for the role of Cordelia Chase, During the early airing of Buffy the Vampire Slayer, she made her first major movie appearance in the slasher–thriller I Know What You Did Last Summer (1997), co-starring Jennifer Love Hewitt, Ryan Phillippe and Freddie Prinze, Jr.
The film, loosely based on the 1973 novel of the same name, centers on four friends who are being stalked by a killer, one year after covering up a car accident in which they were involved.