Gia Marie Allemand was born to Eugene and Donna Allemand in the Howard Beach neighborhood of Queens, New York City, and grew up in the borough of Staten Island and nearby in suburban Long Island, where she graduated from Lindenhurst High School in 2001. Allemand’s parents separated in 1992, later divorcing; Donna Allemand married Tony Micheletti who she described as closer to Gia than her biological father.

Gia began modeling early, and as a baby she appeared in Johnson & Johnson ads and as a Gerber Baby. As a teenager, Allemand initially never thought about a career in modeling. However, at 19 she began modeling after she was asked to enter a swimsuit competition she says she won. Allemand finished second in the Miss Hawaiian Tropic competition and the Miss Red Hot Taj Mahal Super Bowl contest in 2005. She is best known for appearing as a swimsuit model in Maxim in 2007. In 2008, she was named Miss Bikini-USA’s Model of the Year. The following year Allemand placed first in the bikini short class of the NPC Arnold Amateur Championships. In addition to modeling, Allemand worked for the modeling and creative-fields consultancy Dream It Make It.

Allemand said in an interview that she has always had a passion for acting and performing. She was a former professional ballet dancer, but her dancing career was shortened after she injured her hamstring and Achilles tendon. Nevertheless, Allemand took acting classes in high school and at Hartford College. In 2010, she was selected to play a role in an upcoming film produced by Brett Ratner on the life of actor Gianni Russo. She was cast to play the supporting role of actress Ava Gardner. Russo cast her for the role saying, “Gia looks a lot like Ava, but it’s really the passion that she had that convinced me to cast her.”

Allemand’s work in television began when she was selected as a cast member on ABC’s reality show The Bachelor: On the Wings of Love, season 14 of The Bachelor series which first aired on January 4, 2010. The show placed her with 24 other women all contending for the affection of pilot Jake Pavelka. She was the second to the last contestant eliminated by Pavelka. On February 18, 2010 Allemand appeared on The Ellen DeGeneres Show, where she discussed her life after being on The Bachelor.

Afterwards, Allemand joined the cast of ABC’s Bachelor spinoff, Bachelor Pad. The show premiered August 9, 2010 on ABC. She entered the show as the only contestant in a committed relationship. Allemand cited the relationship as the reason why she refused to participate in the show’s “kissing contest” game which led to her elimination in the third episode. Before appearing on Bachelor Pad Allemand was featured in a special edition of ABC’s 20/20: Inside the Bachelor: Stories Behind the Rose.  Allemand appeared in the episodic short film Ghost Trek: The Kinsey Report, a horror-comedy about a paranormal reality show, in which Allemand plays the role of producer Shawna Leibowitz.

On August 12, 2013, Allemand was admitted to University Hospital in New Orleans after an attempted suicide by hanging. She was declared brain dead and removed from life support two days later at age 29. At the time of her death, she was living in New Orleans and dating NBA player Ryan Anderson of the New Orleans Pelicans.  A video tribute for Allemand aired during a 2014 episode of The Bachelor.  Her funeral was held at Trinity Grace Church, a nondenominational Christian church in the Chelsea neighborhood of Manhattan.