Kiara first began performing in adult movies movies in 2011. Mia is bilingual, speaking both English and Spanish. Kiara Mia was born in Los Angeles. She graduated from Arroyo High School in El Monte, California. According to Kiara, she grew up in a "conservative and strict Latino home". During her 20's, Kiara attempted to break into Hollywood. In 2005, Kiara landed a role in Harsh Times, a film with Christian Bale and Eva Longoria. After failing to land more roles, Kiara was struggling financially. She then began doing web cam shows on the internet and studying graphic design.

In 2011, Kiara broke into the adult entertainment industry when she starred in Big Tits at School, at the age of 35. Her hourglass figure and slight resemblance to Kim Kardashian propelled her to success. Throughout the 2010s, Kiara enjoyed a successful pornographic career by starring in more than 90 films. Kiara received multiple award nominations from the AVN Awards in 2015 and 2016. In an interview with male porn actor Lexington Steele, Steele named Kiara as his favorite Latino female performer.[4] In 2015, Kiara released Keeping Up with Kiara Mia, a porn parody of Keeping Up With the Kardashians. Alongside the adult film, Kiara opened her own website that offered a "boyfriend experience" and "VIP Snapchat" memberships.

During the summer and fall of 2018, Kiara enjoyed a spotlight in mainstream tabloids when she began dating NFL quarterback Jimmy Garoppolo. In July, Kiara and Garoppolo were seen going on a date at a Beverly Hills restaurant. The encounter was publicized in celebrity tabloid websites, such as TMZ. As Kiara was enjoying new found attention, Garoppolo was scrutinized in the press for courting a porn star. Weeks later, Garoppolo suffered a season-ending injury.