Growing up in Las Vegas, Nevada, Missy's mother was a hospital worker (who worked the graveyard shifts) while her father worked a variety of jobs including truck driving and paramedic work. Her parents apparently split up after she was 12 - an age where, according to her, she engaged in sexual activities and troublemaking at school from the eighth grade onward. By the time she graduated high school, she was 17 and had slept with (in her estimation) 150 male companions. After graduation, she worked service-sector jobs (notably J.C. Penney and Domino's Pizza), and experimented with recreational drugs including marijuana. Monroe began her adult entertainment career in 2003 as a topless dancer, the specific club she worked at was the famous Cheetah's. Her entry into pornographic modeling was a photoshoot in April 2003. From October 2003 to April 2004, she moved to Los Angeles and stopped working in the industry due to her romantic relationship with a mechanic. Due to his later job displacement and his unwillingness to have her work, she ended the relationship with him. For a time, she roomed with pornographic actress Genesis Skye for roughly six weeks in 2006; a major fight between the two became the focus of news and tabloid reports, resulting in Genesis Skye's moving out of the apartment.

Monroe often receives aggressive anal sex, and launches out plenty of dirty talk during her scenes. She is also known as a 'squirter', often appearing to ejaculate during sex scenes. As of October 8, 2007 the IAFD has her credited with performances in 223 DVDs and the Adult Web Movie Database has her listed on 49 different websites in 67 scenes covering a wide range of genres including interracial, anal and female ejaculation (squirting). Monroe gave birth on August 19 2007 to a son, named Dylan James.