She has been playing the role of Marina Cooper on Guiding Light from May 2004 to September 2009 and received her first nomination for a Daytime Emmy Award in 2006 for Outstanding Younger Actress.

Bruno has a BFA in Theater from Otterbein College in Westerville, Ohio and was hired straight out of college for the role of Marina.

She also previously made headlines when, while attending Jesuit High School, a Catholic school in Portland, Oregon, the school's administration did not allow her to appear in the title role of the school's production of Jesus Christ Superstar. The story garnered national media attention. Mandy eventually appeared in the production in the role of Pilate.

Bruno performed the role of Eponine in the Broadway revival of Les Misérables at the Broadhurst Theater from April 24, 2007, through June 17, 2007.

Mandy is engaged to her Guiding Light co-star Robert Bogue.