Downey attends Thornhill College, a Catholic girls school. Her mother, Maureen O’Reilly Downey, a homemaker with an interest in the performing arts, dies of a heart attack at age 48 when Downey is 10 years old. Her father, Patrick Downey, is a schoolteacher by training but works as a mortgage broker. He dies when Downey is 20. Originally, she plans to be a painter and earns a Bachelor of Arts at Brighton College of Art. She studies BA(Hons) Expressive Arts at Brighton Polytechnic, which later becomes the University of Brighton. Based at the Falmer campus she combines Art and Drama for her degree.
Downey joins the Abbey Players in Dublin and tours the United States in a production of The Playboy of the Western World. She moves to New York after an agent, whom she met during the tour of The Playboy of the Western World, suggests she has potential for success there. She takes a job as a coat checker at an Upper West Side restaurant before getting cast in Broadway shows. The production leads to a nomination during the Broadway run for the Helen Hayes Award for Best Actress in 1991. She also stars on Broadway in The Circle with Rex Harrison and also at the Roundabout Theater and The Public Theater in New York City.
For nine seasons Downey plays Monica, the tender-hearted angel and employee of Tess (played by Della Reese), on the CBS television series Touched by an Angel (1994-2003), for which she earns multiple Emmy and Golden Globe Best Actress nominations. She plays the leading role of Jacqueline Kennedy Onassis in the miniseries A Woman Named Jackie for NBC.
Downey stars in and is executive producer for a number of hit television movies for the CBS network. She is an ambassador for Operation Smile, a nonprofit medical service organization. On August 11, 2016 she is honored for her work as an actress and producer with a star on the Hollywood Walk of Fame. In her acceptance speech, she dedicates her star to the people of Derry and anyone who ever “walked Hollywood Boulevard with a dream in their hearts.”
As President of Lightworkers Media, the family and faith division of MGM, Downey and her husband, Mark Burnett, produce the Emmy-nominated miniseries The Bible for History channel, which airs in 2013 and is watched by over 100 million people in the United States. She also stars in the miniseries in the role of Mary, mother of Jesus. They also executive-produce the feature films Son of God (2014), Little Boy (2015), Woodlawn (2015), and Ben-Hur (2016) starring Jack Huston, Toby Kebbell and Morgan Freeman.
Variety recognizes Downey and Burnett as “Trailblazers” and lists Downey as one of Variety’s “100 Most Powerful Women in Hollywood.” The Hollywood Reporter includes the couple in their “Most Influential People of 2013” and Downey as one of the “100 Women in Entertainment Power” in 2014. She is honored on Variety‘s “Women of Impact in 2014.” Downey and Burnett also produce The Dovekeepers (2015) based on the best selling book by Alice Hoffman for CBS and A.D. The Bible Continues (2015) for NBC, Women of the Bible for Lifetime, and Answered Prayers (2015) for TLC. Downey is the executive producer of the documentary “Faithkeepers” about the persecution of Christians in the Middle East.
Downey is the author of two books, Love Is a Family (2001) and Box of Butterflies: Discovering the Unexpected Blessing All Around Us (2018).