Leah Donna Dizon was born in Las Vegas, Nevada on September 24, 1986. Her mother is of French descent while her father is of Filipino and Chinese descent. Her parents worked as casino dealers. Dizon is the fourth of six children: she has two older brothers, an older sister, and two younger brothers. In an interview, she explains that she listened to rock and R&B music and trained in dance since the age of 12. Dizon has said that her mother was "very strict and monitored [Dizon's] spending habits". When she was 14 years old, she worked at a clothing store and eventually saved enough money to travel to Japan alone for a trip.

She attended the Las Vegas Academy of Performing Arts for her freshman and sophomore years but graduated from the public Eldorado High School in 2004, where she became active in theater. At the age of 18, Dizon relocated to Los Angeles, California and attended college as a film major for her freshman year.

In March 2006, Dizon moved to Tokyo and began Japanese lessons alongside voice training. She released her first photobook, Petite Amie (which means "girlfriend" in French), in October 2006—Petite Amie was ranked as the third best-selling photobook of 2006 and 2007. A few pictorials for various magazines followed.

Dizon made her musical debut under Victor Entertainment on February 14, 2007 with the single "Softly". This was followed by "Koi Shiyō", and "L・O・V・E U". which also peaked at number 7 on the Oricon Weekly Chart. The title track is described as a "grooving, up-tempo dance song" and the single features 2 B-sides: "Could you be that one?" and "Aishiteru: Love Story" (アイシテル～ Love Story). Koi Shiyō was used in a Lotte TV advert, while "Could you be that one?" was featured in a PlayStation 3 Ninja Gaiden Sigma TV advert, with Dizon starring in both commercials. In September 2007, Dizon released her debut album, Destiny Line, under Victor Entertainment. The CD+DVD Edition contains 14 tracks, 10 of which she penned herself on the single PVs alongside a special album PV "Again and Again". The CD+1 only edition contains the digitally-released remix of "Koi Shiyō", called "Koi Shiyō (Yasutaka Nakata-Capsule Mix)".

In February 2008, Dizon began dating her Stylist Bun (born 1979), whom she had met while shooting the music video for Love Paradox. On October 10, 2008, while three months pregnant, Dizon married Bun in a traditional Japanese ceremony. These initial stages were chronicled and announced during her Communication!!! Album Tour several days after the marriage. The couple's daughter, Mila (美蘭, Mira), was born on April 24, 2009.

On February 14, 2010, Dizon appeared on live television and discussed making cookies for Bun. Subsequently, she confessed that their relationship had been aversive ever since the birth. That same month, she was featured in a spread for Glamorous Magazine, where she discussed motherhood and her hopes to return to the entertainment industry. It was her first magazine cover in nearly two years. On October 31, 2010, she announced that she and Bun had separated and filed for divorce earlier that month, and she was seeking full custody of their child. According to Dizon, the split was due to "busy schedules and inability to meet regularly differing opinions toward raising children" alongside "irreconcilable differences". According to a statement released on February 22, 2011 by Dizon's agency, Dizon received full custody of their daughter Mila and details of their arrangement were private. Their divorce was finalized in December 2010. Dizon subsequently attended the Stella Adler Studio of Acting in New York City, where she graduated in December 2012. After graduating, Dizon stated that she would like to return to Japan for work in the Future.

In June 2011, Dizon filmed commercials in Manhattan for Shonan Cosmetic Surgery Clinic. The commercials were released on August 17, 2011.

On December 14, 2012, Dizon announced that she had signed a contract with a talent agency in the US, and would also be accepting any offers for Japanese work if she were to receive any.

It was reported by the magazine Joseijishin in June 2013 that Dizon's ex-husband Bun had stopped paying child support for their daughter, which was the main reason Dizon returned to Japan. "Apparently his Business partner went bankrupt. But he needs to continue his responsibility for his daughter," Dizon is reported to have said. She now lives in Las Vegas with her mother and daughter.

While living in Los Angeles, Dizon worked as a promotional model for local car shows. Eventually, her photographs were posted online. It was reported that there were 2 million Google hits within an entire year, with the majority of the viewers being located in China and Japan. Much of the attention received was attributed to her unique looks. She was asked by many Japanese fans—who had seen her photographs—to work in their country, which eventually prompted her to submit several demo tapes and dance videos to Victor Entertainment. An agent offered and signed her to a recording contract.