In Marilyn Manson's music video for "Tainted Love", which was featured on the movie's soundtrack, she made a cameo appearance as her character Catherine Wyler.

[13] In 2006, she starred in Brian De Palma's The Black Dahlia in which she plays the young aspiring actress Elizabeth Short, whose mutilation and murder in 1947 remains unsolved.

"[15] J. R. Jones described her performance as "haunting" and that the film's fictional screen tests "deliver the emotional darkness so lacking in the rest of the movie.

[21] On October 9, 2013, it was mentioned on the Showcase blog that Kirshner would be one of several guest stars in season four of the television series Lost Girl.

On September 5, 2019, Entertainment Tonight's news outlet ET Online reported that Kirshner would play a character in Lifetime's film The College Admissions Scandal with co-star Penelope Ann Miller in roles inspired by real-life actresses Lori Loughlin's and Felicity Huffman's involvement in a massive college admissions bribery scam.

"[23] In September 2020, it was announced that Kirshner would co-star with Ben Savage in a Hallmark Channel holiday film entitled Love, Lights, Hanukkah!, which premiered on December 12, 2020.

[24] In October 2008, after seven years in production,[25] Kirshner published the book I Live Here,[26] which she co-produced with ex-Adbusters staffers Paul Shoebridge and Michael Simons,[27] as well as writer James MacKinnon.

In the book, four different groups of women and children refugees from places such as Chechnya, Juárez, Burma and Malawi tell their life stories.

The book features original material from well-known comic and graphic artists including Joe Sacco and Phoebe Gloeckner.