A pioneer of stride piano, he was one of the most important pianists in the early era of recording, and like Jelly Roll Morton, one of the key figures in the evolution of ragtime into what was eventually called jazz.

[1] Johnson was a major influence on Count Basie, Duke Ellington, Art Tatum, Thelonious Monk, and Fats Waller, who was his student.

[5] Johnson later cited the popular African American songs and dances he heard at home and around the city as early influences on his musical taste.

[9] In 1914, while performing in Newark, New Jersey with singer Lillie Mae Wright, who became his wife three years later, Johnson met Willie "The Lion" Smith.

[9] Before 1920, Johnson had gained a reputation as a pianist on the East coast on a par with Eubie Blake and Luckey Roberts and made dozens of player piano roll recordings initially documenting his own ragtime compositions before recording for Aeolian, Perfection (the label of the Standard Music Roll Co., Orange, New Jersey), Artempo (label of Bennett & White, Inc., Newark, New Jersey), Rythmodik, and QRS during the period from 1917 to 1927.

These technically challenging compositions would be learned by his contemporaries, and would serve as test pieces in solo competitions, in which the New York pianists would demonstrate their mastery of the keyboard, as well as the swing, harmonies, and improvisational skills which would further distinguish the great masters of the era.

As the swing era began to gain popularity within the African American communities, Johnson had a hard time adapting, and his music would ultimately become unpopular.

Although by this time, he was an established composer, with a significant body of work, as well as a member of ASCAP, he was nonetheless unable to secure the financial support that he sought from either the Rosenwald Foundation or a Guggenheim Fellowship; he had received endorsement for each from Columbia Records executive and long-time admirer John Hammond.

[citation needed] Johnson's appearances at the Spirituals to Swing concerts at Carnegie Hall in 1938 and 1939 were organized by John Hammond, for whom he recorded a substantial series of solo and band sides in 1939.

He was a regular guest star and featured soloist on Rudi Blesh's This is Jazz broadcasts, as well as at Eddie Condon's Town Hall concerts.

[citation needed] Never satisfied with the state of his craft, he continued his musical education, begun in the 1930s, studying with Maury Deutsch, who could also count Django Reinhardt and Charlie Parker among his pupils.

In the late 1940s, Johnson had a variety of jobs, including jam sessions at Stuyvesant Casino and Central Plaza, as well as becoming a regular on Rudi Blesh's radio show.

He wrote waltzes, ballet, symphonic pieces and light opera; many of these extended works exist in manuscript form in various stages of completeness in the collection of Johnson's papers housed at the Institute of Jazz Studies, Rutgers University, Newark, New Jersey.

Along with Fats Waller and Willie 'The Lion' Smith ('The Big Three'), and Luckey Roberts, Johnson embodies the Harlem Stride piano style, an evolution of East Coast ragtime infused with elements of the blues.

Lastly, while ragtime was for the most part a composed music, based on European light classics such as marches, pianists such as Waller and Johnson introduced their own rhythmic, harmonic and melodic figures into their performances and, occasionally, spontaneous improvisation.

Comparison of many of Johnson's recordings of a given tune over the years demonstrates variation from one performance to another, characterized by respect for the melody, and reliance upon a worked out set of melodic, rhythmic, and harmonic devices, such as repeated chords, serial thirds (hence his admiration for Bach), and interpolated scales, on which the improvisations were based.

Johnson's musical legacy is also present in the body of work of his pupil, Thomas "Fats" Waller, as well as scores of other pianists who were influenced by him, including Art Tatum, Donald Lambert, Louis Mazetier, Pat Flowers, Cliff Jackson, Hank Duncan, Claude Hopkins, Duke Ellington, Count Basie, Don Ewell, Johnny Guarnieri, Dick Hyman, Dick Wellstood, Ralph Sutton, Joe Turner, Neville Dickie, Mike Lipskin, and Butch Thompson.

Unmarked since his death in 1955, his grave was re-consecrated in 2009 with a headstone paid for with funds raised by an event arranged by the James P. Johnson Foundation, Spike Wilner and Dr. Scott Brown.

By far, the most complete CD collections of his work, including alternate takes, has been produced by Michael Cuscuna and his associates at Mosaic Records with the box Classic James P. Johnson Sessions, 1921-1944,[20] that includes all of Johnson's piano solos, band sides, and blues accompaniments, done during this period, for the major commercial labels, exclusive of Decca/Brunswick, and RCA Victor.

James P. is also featured prominently in the Mosaic re-issues of the Commodore (under Max Kaminsky's name) and the HRS labels (Pee Wee Russells's Rhythm Makers).

This three-LP collection contains 40 sides recorded from 1921 to 1945, and is supplemented with extensive liner notes, including a biographical essay by Frank Kappler, and criticism of the musical selections by Dick Wellstood, and the musicologist, Willa Rouder.