Jennifer Lynn Lopez Rodríguez was born on July 24, 1969, in the Castle Hill neighborhood of The Bronx, New York. The middle child of Puerto Rican parents Guadalupe Rodriguez and David Lopez, she has an elder sister, Leslie, and a younger sister, Lynda. David worked the night shift at the Guardian Insurance Company, before becoming a computer technician at the firm, while Guadalupe was a homemaker. When Lopez was born, the family was living in a small apartment. A few years later, her parents had saved up enough money to be able to purchase a two-story house, which was considered a big deal for the relatively poor family. At the age of five, Lopez began taking singing and dancing lessons. She toured New York with her school when she was seven years old Her parents stressed the importance of work ethic and being able to speak English. They encouraged their three daughters to put on performances at home; singing and dancing in front of each other and their friends so that they would stay "out of trouble".Lopez spent her entire academic career in Catholic schools, finishing at Preston High School. In school, Lopez did gymnastics, ran track on a national level and was a member of the school's softball team. She excelled athletically rather than academically, competing in national track championships. In 1984, at the age of fifteen, she began dating David Cruz, her first boyfriend.
While attending her final year of high school, Lopez learned about a film casting that was seeking several teenage girls for small roles. She auditioned and was cast in My Little Girl (1986), a low-budget film co-written and directed by Connie Kaiserman. Lopez acted as Myra, a young woman at a center for troubled girls. After she finished filming her role in the film, Lopez realized that she wanted to become a "famous movie star". To please her parents, though, she enrolled in Baruch College, only to drop out after one semester. She told her parents her dream of becoming a movie star, but they insisted that it was a "really stupid" idea and that "no Latinos did that". The differences in opinions led Lopez to move out of their family home and into an apartment in Manhattan. During this period, Lopez performed in regional productions of the musicals: Jesus Christ, Superstar! and Oklahoma. From there, she was hired for the chorus in a Golden Musicals of Broadway, which toured Europe for five months. She was unhappy with the role, as she was the only member of the chorus to not have a solo. She later got a job on the show Synchronicity in Japan, where she acted as a dancer, singer and a choreographer.

Musical style
Since the beginning of her music career, Lopez has explored various music genres including Latin pop, dance, R&B, hip hop, rock, funk, house and salsa. Ed Morales stated in The Latin Beat: The Rhythms And Roots Of Latin Music From Bossa Nova To Salsa And Beyond (2003) that her music explored both "the romantic innocence of Latin music", and hip hop. Despite being influenced by Latin musical styles (ranging from salsa to bachata) as a child, it was the 1979 hip hop song "Rapper's Delight" by hip hop trio The Sugarhill Gang that "changed" her life. As she forayed into the music industry, Lopez infused Latin music together with the hip hop sound she loved, which she branded Latin soul.
While her first two albums included funk, dance, urban and Latin-flavored music,Lopez's third album This Is Me... Then was inspired by '70s music. Rebirth, her fourth album, explored pop rock while utilizing stronger use of percussion and horns. Her sixth and seventh studio albums, Brave and Love?, delved further into a dance music direction. Lyrically, Lopez's music revolves around love. However, she has also explored themes such as dance, sex, female empowerment, and self-loathing. She often includes personal experiences in her songs, such as her relationship with Ben Affleck on tracks "Dear Ben" and "He'll Be Back". Songs from Love? such as "Until It Beats No More" and the personal "One Love" are also based on Lopez's own love life.
Lopez has been influenced by artists such as Tina Turner, James Brown, Michael Jackson, Madonna and Barbra Streisand. Critics have considered Lopez's soubrette vocal type to be limited, though "radio friendly". Having experienced insecurity about the strength of her voice herself, Lopez has since grown in confidence, crediting former husband Marc Anthony for helping her. Rolling Stone observed: "Instead of strained vocal pyrotechnics, Lopez sticks to the understated R&B murmur of a round-the-way superstar who doesn't need to belt because she knows you're already paying attention [...] She makes a little va-va and a whole lot of voom go a long way." Entertainment Weekly criticized her vocal performance for lacking the trademark "husky-voiced voluptuousness" she has in her films. The Baltimore Sun regards Lopez as having a "breathy" stylistic range, but lacking personality. Today Music opined: "like Madonna and Janet, people don’t listen to J.Lo for the poignant lyrics—she’s best when riding a dance groove".