Natasha, of Hawaiian, Chinese, Filipino and Caucasian heritage, was born in Kahuku, Hawaii. Natasha started her first training camp with the full United States Women's National Soccer Team in February 2006. She made her full Women's National Team debut at the 2006 Algarve Cup in Portugal, scoring in her first two games against Denmark and France, as a substitute.

Injured her shoulder in her final college game of 2004, then re-injured it again in her first U-21 camp of 2005, necessitating surgery, and did not get called into an U-21 camp until January 2006. At the 2008 Summer Olympics in Beijing, Kai scored the winning goal in overtime to lead the U.S. past Canada in the quarterfinal round.

Natasha is also known for having 19 tattoos, one of which being a "sleeve" on her right arm. She enjoys singing and takes after her father Benny Kai, who is a professional singer at the Polynesian Cultural Center in Laie, Oahu.

She recently came out as a lesbian, when she told NBC about her "nasty break-up with my girlfriend".