Melia was born in Galway, Ireland and moved to the US when she was five years old. A student of ballet, she trained at Walnut Hill School for the Performing Arts, Boston Ballet, the Central Pennsylvania Youth Ballet and the Centre de Danse International in France. She studied at Sarah Lawrence College and as a Theater and English Major at Trinity College, Dublin. Following her graduation she moved to New York City to begin a career in acting. Her work in TV and film has featured her alongside actors such as Sissy Spacek, Dustin Hoffman, Keir Dullea, Jake Gyllenhaal and Beau Bridges.
Melia has spent much of the past ten years performing on the stage. She has worked with American Repertory Theater, Moscow Art Theater and the British 'immersive' company, Punchdrunk. From 2009 - 2013 Melia was a senior company member and performer in the award winning production of Sleep No More (Boston and NYC runs) for which she created and originated the role of Hecate. She also created additional material for the role of Matron Lang. In 2012 she was part of the MIT/ NESTA project at Sleep No More which utilized online gaming and live video. Melia has performed in Off-Broadway productions such as Macbeth (by Theater for a New Audience), Anne Frank and Me (with the American Jewish Theater), and the Irish Repertory Theater's new plays series. Regionally she has worked at Berkshire Theatre Festival, The Huntington Theatre, Pittsburgh Public Theatre, Shakespeare Center of Los Angeles, GeVa Theatre and Great Lakes Theatre Festival.
In 2014 she founded Walden Shakespeare which is in residence in Massachusetts at NARA Park Amphitheater. In 2017 she is premiering The Gertrude Bell Project, a solo show based on the life of British explorer, politician and spy Gertrude Bell, at Boston Center for the Arts.
She received an MFA from the American Repertory Theater/Moscow Art Theater Institute at Harvard University.
- Frank and Lamar (web series).. Mrs. Chapman
- American Democracy... Nadia
- The Good Wife... Mom
- JAG .... Mary Tenney (1 episode, 2002) - All Ye Faithful (2002) TV episode .... Mary Tenney
- Moonlight Mile (2002) .... Diana Floss
- My Best Friend's Wife (2001) (as Careena Melina) .... Wife; aka "Grownups" - USA (video title); aka "Steve & Claire & Eric & Ami" - USA (TV title)
- XCU: Extreme Close Up (2001) .... Parker Eastman Clarke
- 18 Wheels of Justice .... Sarah (1 episode, 2001) - Honor Thy Father (2001) TV episode .... Sarah
- Under Hellgate Bridge (2000) .... Doreen
- Songs in Ordinary Time (2000) (TV) .... Alice Fermoyle
- Touched by an Angel .... Fiona (1 episode, 2000) - Life Before Death (2000) TV episode .... Fiona
- Two Way Crossing (1998) .... Sara
- Conn Ua Mellaig, Bishop of Annaghdown, died 1202.
- Tomas Ó Mellaig, Bishop of Annaghdown, c.1242-1247/50.
- Tomás Ó Mellaig, bishop-elect, fl. 1329.
- Cian Melia, Irish showjumper.