Louis Armstrong (4 August 1901 – July 6, 1971), nicknamed Satchmo or Sachimo and Pops, was an American jazz trumpeter and singer.

Coming to prominence in the 20s as an innovative cornet and trumpet virtuoso, Armstrong was a foundational influence on jazz, shifting the music's focus from collective improvisation to solo performers. With his distinctive gravelly voice, Armstrong was an influential singer, demonstrating great dexterity as an improviser, bending the lyrics and melody of a song for expressive purposes. He was also greatly skilled at scat singing, or wordless vocalizing.

Renowned for his charismatic stage presence, Armstrong's influence extended well beyond jazz, and by the end of his career in the '60s, he was widely regarded as a profound influence on popular music in general: critic Steve Leggett describes Armstrong as "perhaps the most important American musician of the 20th century."