In the third grade her teacher told her that she was an actor and Anna always knew that she wanted to act. Although during her college career she considered going into marine biology or law, as a sophomore she tried out and got a part in a play. After that, she desided to persue her dream.

She graduated from Lincoln Academy in 1990 and continued her experience with Middlebury's professional acting company in Vermont while waiting tables. After recieving her B.A. she went to San Francisco to gain a masters through the American Conservatory Theater. Here she met Eric Siegel, also an actor, and they are now married. After graduating, they moved to New York City, where Anna waited tables and checked coats to get by, while working towards a full time acting career.

They lived in Brooklyn for a while and later moved to Los Angeles where Eric has lived most of his life. Anna's parents ,David and Louise Belknap, still live in Damariscotta and Anna and Eric bought a house with waterview i Waldoboro, not far from her hometown, where they plan to spend about a month each year.They are both members of the Rude Mechanicals Theatre Company in New York.

In her sparetime Anna enjoys hiking, yoga, camping, tennis and scouring for thrift stores in search for old furniture.

Anna's stage credits include the Off Broadway production of Metamorphoses at New York's Second Stage Theatre, as well as roles at the Mark Taper Forum, the Globe Theater, the Huntington Theatre, the Westport Country Playhouse and the Williamstown Theater Festival. Anna also played the part of Marina in Darko Tresnjak's rendition of William Shakespeare's Pericles, for which she received a San Diego Theater Critics Circle Craig Noel Award for Outstanding Performance in 2002.

Her acting career started onstage but her career in on-screen homicide investigation took off in the late 1990s when she picked up a role on "Homicide: Life on the Street." Belknap was able to land a few bit parts in series such as Law and Order. That was followed by roles in The Handler and Medical Investigations. Her big break came as she was cast as Detective Lindsay Monroe in CBS's, CSI: New York. She is married and lives with her husband and young daughter.