As far as who was the first one who played jazz and when it was played for the first time, there is lack of evidence and a lot of different opinions have been heard. But there is one think about Jazz’ origins for sure and that is the place from which it has originated: Storyville, the red-light district of New Orleans.
Jazz music was born during the 20th century in New Orleans due to two distinctive factors. At the time New Orleans was a thriving port city with a strong nigh life and home of the Creoles subculture. The Creoles were free Blacks who spoke French and Spanish that came to America in 1803 because of the Louisiana Purchase and in 1821 due to Louisiana statehood. They lived east of Canal Street and in the 19th century they managed to rise on the highest levels of New Orleans society by becoming prominent in the economic and cultural life of the city. The fact the New Orleans was a meeting point of people and musicians from all different places, ethnicities and traditions made the creation of jazz music possible.
Jazz shares aspect of folk, popular and art music and has element of blues, brass band music, hymns and spirituals, minstrel music and ragtime. It evolved through a mixture of European and African music elements. From the European tradition, it took its harmony (chords that accompany the tunes) and instruments (saxophone, trumpet, trombone, string bass and piano). From the African tradition, it took the rhythm, the blues and the tradition of playing a music instrument (banjo, guitar, percussion) in one’s own way, making self-expression possible. The improvisation element came from both traditions.
Sources: http://www.redhotjazz.com/originsarticle.html , http://www.oxfordmusiconline.com/subscriber/article/grove/music/J223800?q=jazz&search=quick&pos=1&_start=1 , http://www.britannica.com/EBchecked/topic/301986/jazz