Yamashita began to study the guitar at the age of eight with his father, Toru Yamashita. In 1972, aged eleven, he won the Kyushu Guitar Competition. Four years later, he was awarded First Prize in the All Japan Guitar Competition. In 1977, he won three important international competitions - the Ramirez in Spain, the Alessandria in Italy and Paris Radio France Competition, being the youngest winner ever recorded.

In 1978, Yamashita made his debut in Japan and, in the following year, traveled to Europe. While still in his twenties, he made his first appearances in Canada's Toronto International Guitar Festival and gave a solo recital in the Musikverein (Grosser Saal) in Vienna, he also performed in the US and UK. He gave solo recitals in concert halls around the world such as the Lincoln Center and has performed with a variety of orchestras and conductors in Europe, North America and Asia. In 1989, the Casals Hall in Tokyo, considered to be one of the finest auditoriums in the world, presented a series called The World of Kazuhito Yamashita, comprising seven concerts in 12 months. The high point of the concerts was Castelnuovo-Tedesco's 24 Caprichos de Goya in a single performance. The series concluded with Bach's six sonatas and partitas over two consecutive nights; a recital series was continued in 1994 and 1999.

In addition to solo performances, Yamashita also plays duo, as well as with chamber music ensembles, orchestras and internationally acclaimed artists, such as Leonard Slatkin with the London Philharmonic Orchestra, Rafael Frühbeck de Burgos, Antoni Ros Marbà, Garcia Navaro, Pedro Halffter, Hiroyuki Iwaki, NHK Symphony Orchestra, Los Angeles Chamber Orchestra, Orquesta de la RTVE, Claudio Scimone e I Solisti Veneti, James Galway (flute), Gary Karr (double bass), Michala Petri (recorder), The Tokyo String Quartet etc. In the 4th Santo Tirso International Guitar Festival, held in 1997, he played four guitar concertos in one night with the Cordoba orchestra, conducted by Leo Brouwer. Most recently, he is active in the guitar quartet Kazuhito Yamashita & Bambini. This quartet, consisting of Yamashita and his children, has performed at two international festivals in Italy, the Seoul Art Center in Korea, Portugal, Cordoba Festival in Spain, San Francisco Herbst Theatre and several cities throughout Japan.

Yamashita has made almost 80 recordings and numerous original arrangements of such works as Mussorgski's Pictures at an Exhibition, Stravinsky's Firebird, Rimsky-Korsakov's Scherezade and Dvorák's Symphony of the New World. He has recorded for BMG (RCA), Crown Classics, Japan Victor, King Records and Alfa Records. His recordings include 16 CD's with the complete works of Fernando Sor, and a collection of 5 CD's containing J.S. Bach's sonatas and partitas for violin, cello, lute and flute (BWV 995-1013), all which he himself transcribed for the guitar. His recording of Mussorgsky's Pictures at an Exhibition, released in 1981, was awarded the Deutsches Grammophon Award.

Yamashita is an enthusiastic proponent of new works for the guitar and has given the world premier of more than 60 new compositions. In this regard, his world premier and presentation of the works of the Japanese composer Keiko Fujiie is notable. In 1999, he received the National Arts Festival Grand Prize from the Japanese Government's Agency for Cultural Affairs for his CD recording of Japanese Guitar Music 1923-1948.

Yamashita's early arrangements of Pictures at an Exhibition, Stravinsky's Firebird Suite, Dvorák's New World Symphony no. 9 in E Minor, and others, broke boundaries in terms of solo guitar expression and virtuosity.

In 2004 "Kazuhito Yamashita+bambini" was founded by Kazuhito, his two daughters and elder son, for the risorgimento of a quintessential and older musical tradition (This recalls a bygone era of both the East and the West when such music was known and valued and whose echoes can still be heard in the classic 11th century novel "The Tale of Genji") by performing original pieces written for them by Keiko Fujiie, based on her Oriental view of the world. In 2010, their younger son joined them and they were renamed "Kazuhito Yamashita Family Quintet". They have already appeared in three festivals in Italy, Cordoba festival in Spain in 2007 and 2011, has also performed in Portugal, Korea, Vietnam, Singapore, Japan and United States.