Monica Louise Horan was born on January 29, 1963, in Darby, Pennsylvania, to Selma and Robert J. Horan. She graduated from Archbishop Prendergast Catholic High School for Girls in 1980 and went on to Hofstra University in Hempstead, New York, where she earned a degree in Theater Performance in 1984.

Monica Horan began her career in off-off Broadway theatre while working as a telephone sales agent for Telecharge. She met her future husband, Philip Rosenthal, at Hofstra, and they married in 1990 after Monica converted to Judaism. The couple currently resides in Los Angeles with their two children, Ben and Lily.

She is best known for her role as Amy MacDougall-Barone on the CBS-TV sitcom "Everybody Loves Raymond," where she appeared in 66 episodes from 1997 to 2005. Her character was Robert Barone's on-again, off-again girlfriend, and later wife.

Her performance earned her a Screen Actors Guild Award nomination in 2005 for Outstanding Performance by an Ensemble in a Comedy Series. She has also guest-starred in various TV shows, including "Hot in Cleveland," "The Middle," and "The Bold and the Beautiful."

Monica Horan has appeared in films such as "Pee-wee's Big Holiday" and "K-PAX." She continues to work in the entertainment industry, taking on various acting roles.