Contreras was born in McAllen, Texas, on December 24, 1986, to Blanca Pérez and Efrain Contreras Puente. Contreras is of Mexican descent and speaks both English and Spanish. She moved to Mexico City in 2002 at age 15 to join the reality show Pop Stars, in which she was a finalist and member of a group, T’detila, who released an album with the same name. In 2003, she took acting classes in the Televisa’s Centro de Educación Artística (CEA) in Mexico City.

In 2005, Contreras portrayed Juanita Sánchez in her debut telenovela, Barrera de amor. In 2006, she participated in a production of Grease. That same year, Contreras played Claudia in the telenovela Duelo de Pasiones. In 2008, she starred in the film Divina Confusion, directed by Salvador Garcini. From 2008 to 2009, Ana also starred as Violeta Madrigal in the telenovela Juro que te amo. In 2009, she played Maura Albarrán in the telenovela Sortilegio. That same year, she appeared as Marcela Garrido in an episode of the TV series Mujeres asesinas and had a special participation in the original Fox series, Tiempo final.

From 2010 to 2011, Contreras played the lead role of Aurora Alcázar on Teresa. She also played Carol in the musical Timbiriche. Contreras later starred in the telenovela La que no podía amar as Ana Paula Carmona from 2011 to 2012.

In 2013, she portrayed Maricruz Olivarez in the telenovela Corazón indomable, a remake of Marimar which achieved international success. In 2014, Contreras appeared in the Mexican film Volando bajo, directed by Beto Gómez. That same year, she was host of the Premios Juventud. In 2015, Contreras played the lead role of Verónica Prado Castelo in the telenovela Lo imperdonable. She sang “Como perdonar”, the telenovela’s theme, on the soundtrack.

Contreras married Alejandro Amaya in a civil ceremony in Las Vegas on April 4, 2013. On May 14, 2014, she sent a press release announcing the permanent separation from him. In February 2016, it was confirmed by her Lo Imperdonable co-star Iván Sánchez that the two were in a relationship. As of 2018, he is no longer in a relationship with Contreras.

In 2015, she also starred in the movie Tunnel 19. Contreras starred as Goyita Vera in Blue Demon in 2016, and as Alejandra Ponce in Por amar sin ley in 2018.

From 2018 to 2019, Contreras starred as Cristal Jennings in the second season of The CW’s prime time soap opera reboot, Dynasty, in her first English language role.