Prior to her participation in the 2005 national Nuestra Belleza México pageant, Perales studied Sciences and Communication at the University of Monterrey and was also doing runway modeling apart from her studies.
In 2004, she participated in her state's pageant and placed first runner-up. Perales competed for the state title again the following year and won the title, becoming her state's representative at the Nuestra Belleza México 2005 pageant held September 2, 2005 in the state of Aguascalientes. In the national competition, Perales subsequently won the Nuestra Belleza México title.
Perales later moved to Mexico City in order to start preparing for the international Miss Universe pageant. She also participated in social and charity events with the Nuestra Belleza Mexico Organization and The Televisa Foundation, helping abused children. On July 23, 2006, Perales represented her country in Miss Universe 2006, held in Los Angeles, California, U.S. She placed in the top ten, competing in swimsuit and evening gown. The competition was won by Zuleyka Rivera of Puerto Rico. Perales was succeeded by Rosa María Ojeda of the state of Sinaloa as Miss Mexico Universe.
In 2007, after the Nuestra Belleza Mexico organization reobtained the franchise for Miss International, Perales was chosen to be the country's representative in that pageant, held in Tokyo, Japan. On October 15, 2007, Miss International 2006, Daniela Di Giacomo of Venezuela crowned her successor Priscila Perales of Mexico as the new Miss International, becoming Mexico's first representative to win that particular title.
During filming in summer 2010, she starred in Univision's hit telenovela, Eva Luna (soap opera), alongside Guy Ecker, Blanca Soto, Susana Dosamantes, Julian Gil, and other actors. Perales played the role of Liliana, a woman hired by Leonardo Arismendi (Julian Gil) to seduce Daniel Villanueva (Guy Ecker). However, she became obsessed with Daniel and was willing to do whatever it took to be with him, even if that meant killing. She was introduced after Eva (Blanca Soto) became the new owner of Publicidad Arismendi, in episode 79.
In 2012, she appeared in Telemundo's hit telenovela Corazón Valiente, alongside Adriana Fonseca, Jose Luis Resendez, Aylin Mujica, Ximena Duque, and many more. She played the role of Nelly, a maid who worked in the Arroyo's household who was obsessed with Pablo Peralta (Jon Ecker), the bodyguard of Emma Arroyo (Vanessa Pose).
In 2013, she filmed Telemundo's telenovela, Pasión Prohibida, alongside Jencarlos Canela, Monica Spear, Rebecca Jones, Roberto Vander and other actors. She played the role of Eliana Ramirez, girlfriend of Bruno Hurtado (Jencarlos Canela).
In 2014, she played the role of Delfina in the telenovela Reina de Corazones. She worked with actors Juan Soler, Eugenio Siller and Catherine Siachoque.