Born in Reykjavik, Iceland, Gunna moved with her family to the United States when she was a little girl. Growing up in Kalamazoo, Michigan, she spent most of her time competing gymnastics, singing in choirs, doing productions at her local community theatre, and appearing in local commercials and print ads.
After studying journalism, theatre and dance in college, she joined the national touring company of "South Pacific," followed by a move to Los Angeles to pursue her dream of a film and television career. After cutting her teeth in LA, Gunna moved to New York City, where she continues to study and do stage, film, and television work. Gunna has studied improv at Upright Citizens Brigade and acting with the incomparable Bob Krakower, as well as Peggie Feury, Austin Pendleton and Ivan Markota. Some of her credits include "Rescue Me," recurring roles on "The Late Show with David Letterman," and "Late Night with Conan O'Brien" and "Late Night with Jimmy Fallon," 'Nurse Judy' on "The Guiding Light," a national commercial for Sears, sketches on "Saturday Night Live" and "The Jamie Kennedy Experiment," along with other work on "All My Children," "As the World Turns," "Law and Order," and "Sex and the City." Gunna can also be seen in the Julia Roberts film "Mona Lisa Smile," playing the part of Spencer's mistress. She also starred in Ted Lange's play "Lemon Meringue Facade" which premiered off-off-Broadway at The New Perspectives Theatre in NYC.
Gunna is also a very talented guitarist and singer/songwriter. In Los Angeles, as half of "Liquid Melissa," an acoustic duo, she appeared at The Gig, The Crooked Bar, and The Coconut Teazer. She sometimes can be seen performing solo and with her sister, Kristin Wilson Ryan of the band Audio Fiction, in NYC.