American actress and singer whose melodious soprano voice and expressive stage presence made her a primary figure on Broadway in the late 20th and early 21st centuries.

McDonald was raised in Fresno, Calif., by a family of musicians—her parents were pianists and singers, and five of her aunts toured the West Coast as the singing McDonald Sisters in the 1970s. McDonald began taking voice lessons and performing at a local dinner theatre when she was age nine. She continued to perform in high school, assuming the lead roles in several musicals, and pursued further vocal training at the Juilliard School in New York City (B.A., 1993).

Soon after graduating, McDonald was cast in a touring production of The Secret Garden (1993). She quickly attracted attention the following year when she was cast as the fecund Carrie Snow in British director Nicholas Hytner's revival of Carousel. The supporting role earned her a Tony Award. McDonald also demonstrated her abilities as a dramatic actress when she performed the role of a young opera student in Terrence McNally's play Master Class (1996), for which she won another Tony. She made her film debut in the drama Seven Servants (1997), in which she again played an opera singer. Her third Tony was awarded for her stage role as Sarah in McNally's musical Ragtime (1998).

McDonald's appearance in the title role of Marie Christine (1999), a musical retelling of Medea, written especially for her by Michael LaChiusa, marked her first leading role on Broadway. Though the critical approbation elicited by her acting was significant, it was exceeded by the attention paid to her lustrous lyric soprano. She controlled her voice to exquisite effect, navigating a score composed in an amalgam of musical styles. McDonald expanded her repertoire to include Shakespeare with a 2003 performance as Lady Percy in Henry IV. Her turn as Ruth Younger in a revival of Lorraine Hansberry (Hansberry, Lorraine)'s A Raisin in the Sun (2004) secured a fourth Tony. In 2007 McDonald starred as Lizzie Currie in the musical 110 in the Shade. That year she also sang the role of Jenny in the Rise and Fall of the City of Mahagonny.

As well as acting and singing in stage productions, McDonald gave numerous solo performances. At Carnegie Hall in 2005 she premiered a specially commissioned song cycle entitled The Seven Deadly Sins composed of seven pieces written for her by different composers. She was a guest vocalist with the New York (New York Philharmonic), Los Angeles (Los Angeles Philharmonic), and Berlin philharmonic orchestras. Between stage productions she toured in support of her solo albums Way Back to Paradise (1998), How Glory Goes (2000), Happy Songs (2002), and Build a Bridge (2006).

McDonald made a number of film and television appearances. The 1999 television version of Annie featured McDonald as Miss Grace Farrell. She garnered acclaim as the nurse Susie Monahan in the television adaptation of the play Wit (2001) as well as for the reprisal of her Broadway role in the television production of A Raisin in the Sun (2008). In 2007 McDonald took a recurring role in the television drama Private Practice.