Maria Bello was born on April 18, 1967, in Norristown, Pennsylvania, to Kathy, a dedicated nurse and teacher, and Joe Bello, a skilled contractor. Her ancestry is a rich blend of Italian and Polish heritage. Maria's academic journey took her to Villanova University, where she majored in political science, with a strong intention of pursuing a career in law. However, during her senior year, she took an acting class, simply for the fun of it, and discovered a hidden talent. She was soon cast in several off-Broadway plays, including "The Killer Inside Me", "Small Town Gals With Big Problems", and "Urban Planning". Her early television appearances included guest roles on popular shows such as "The Commish" (1991),"Nowhere Man" (1995),"Misery Loves Company" (1995),and "Due South" (1994).
Maria's breakthrough role came when producers Kenny Lenhart and John J. Sakmar cast her in the spy series "Mr. & Mrs. Smith" (1996) as the captivating "Mrs. Smith". They remembered her impressive performance in a failed pilot remake of the classic TV series "77 Sunset Strip" (1958). Although the show was canceled after just eight weeks on the air, Maria's talent was undeniable. She soon landed a significant role on the hit medical drama "ER" (1994) as "Dr. Anna Del Amico", guest-starring in the final three episodes of the third season. The show's producers were so impressed with her performance that they asked her to return as a regular cast member.