[3] She attended Carnegie Mellon University[4] in Pittsburgh for one year before moving to New York City at age 19 to study acting with Uta Hagen[4] at HB Studio.

[5] Finneran's biggest film role was as Judy Rose in the remake of George A. Romero's Night of the Living Dead.

Her film credits include You've Got Mail, Chicken Little, Liberty Heights, Bewitched, Miss Congeniality 2: Armed and Fabulous, and Death to Smoochy.

[12] She also has appeared in My Favorite Year with Tim Curry, John Guare's Bosoms and Neglect, and Smell of the Kill, with Kristen Johnston.

[13] Finneran appeared Off-Broadway at the Laura Pels Theater in the Greg Kotis play Pig Farm, in the original opening cast as Tina.

[14] Finneran appeared in the original cast of Love, Loss, and What I Wore, which opened Off-Broadway at the Westside Theater in September 19, 2009 for a four-week engagement ending on October 18, 2009.

For the first four weeks of the run Ms. [Rosie] O'Donnell is joined by the actresses Tyne Daly, Katie Finneran and Natasha Lyonne, and Samantha Bee..."[15][16] Finneran returned to the show (after her initial four-week engagement) on November 18, 2009, to fill in for Kristin Chenoweth,[17] and continued on in the play in the next four-week rotation as well (from December 14, 2009, to January 3, 2010).