Louis Armstrong was the father of jazz improvisation, the first (and for some the most) influential jazz trumpeter and, with Duke Ellington and Charlie Parker, one of the music's trinity of great creators.
In the 1920s, Armstrong formulated the essential elements of jazz—solos that soared above the basic harmonies of a song, a driving sense of instrument and a deep understanding of the blues.
The elements of jazz are so much an accepted and familiar part of the soundtrack of 20th century life that it's difficult to imagine what it was like without them. Yet to an extraordinary degree, the creative development and the widespread distribution of those elements would not have happened without Armstrong.
The influence upon his musical contemporaries of the recordings Armstrong made in the late '20s with his Hot Fives was overwhelming: "Potato Head Blues" and "Cornet Chop Suey," with their brilliant trumpet improvisations over stop-time rhythms; the soaring, vocalized solos on "West End Blues"; the harmonically complex soloing on "Weather Bird"; the cross-the-bar line rhythms of "Mahogany Hall Stomp."
His influence on the industry is unquestioned.
Bing Crosby's easygoing style, so often seen as a reflection of his personality, was a direct extension of the emotional honesty with which Armstrong approached a lyric.
And it's hard to believe that the justifiably applauded phrasing of Billie Holiday (and Frank Sinatra as well) would ever have evolved the way it did without the prior example of Armstrong's vocals.
Nor would scat singing have become so popular so quickly without Armstrong's genre-defining 1926 recording "Heebie Jeebies." No one learned Armstrong's lessons—in phrasing and scat singing—any better than Ella Fitzgerald, and their recordings together are among the great classics of jazz.