Kaneshiro's mother is from Taiwan and his father from Okinawa, Japan. He was born and raised in Taipei and holds Japanese citizenship
In 1992, Kaneshiro made his singing debut, entering the business with the nickname Aniki, meaning 'older brother' in Japanese. His debut album was Heartbreaking Night (1992). Contracted to EMI, he wrote many of his own Mandarin and Cantonese songs. The following year, his popularity propelled him into acting and he no longer produces any commercial music.
His first movie was Executioners (1993) and this was followed by the critically acclaimed Wong Kar-wai film Chungking Express (1994) and a string of other Hong Kong movies. Later, Kaneshiro starred in the highly successful Japanese TV mini-series God, Please Give Me More Time (1998), allowing him to branch into Japanese movies such as Returner (2002).
Kaneshiro's work, however, is more heavily concentrated in China, Hong Kong, and Taiwan. In 2008 and 2009 he starred in Red Cliff , a high budget film by Hong Kong director John Woo. He has also played the romantic lead in the Zhang Yimou film House of Flying Daggers, and starred alongside Jet Li and Andy Lau in the film The Warlords. Kaneshiro has also became well known in the video game industry portraying the samurai warrior Samanosuke in the Capcom hit Onimusha. In a June 2007 article on the movie site Ain't It Cool News, it was revealed that Kaneshiro will be in the Onimusha movie, reprising his role as Samanosuke and for a 2011 release.
In 2003, Kaneshiro was featured in Time Magazine and was coined as becoming the Asian film industry's Johnny Depp. Moreover, Kaneshiro was interviewed by CNN in the TalkAsia segment in 2006.
Outside of the entertainment business, Kaneshiro has acted as a spokesperson and model for Emporio Armani (2008) as well as, Prada (1998), Lifecard credit card company, VAIO personal computer, Honda, Lipice lips moisturizer, SonyEricsson, Pocari Sweat soft drink, Morinaga chocolate, Volvic, GEOS (eikaiwa) (language school), Petronas oil company, Japan Asia Airways, Hyundai Motor Company, Toyota MarkX ZiO, Mitsubishi Galant, NTT docomo the predominant mobile phone operator in Japan, NTT Yellow Pages, Shiseido, Lycos, UCC Ueshima Coffee Co., Kadokawa Shoten a well-known Japanese publisher based in Tokyo, Rice Burger, Roasted barley tea, One2Free (HK), and Kiwi cold drink, and the most recent Biotherm Homme since 2005