Louis Daniel Armstrong (August 4, 1901 – July 6, 1971), nicknamed "Satchmo", "Satch", and "Pops", was an American jazz and blues trumpeter and vocalist. He was among the most influential figures in jazz. His career spanned five decades and several eras in the history of jazz. Armstrong received numerous accolades including the Grammy Award for Best Male Vocal Performance for Hello, Dolly! in 1965, as well as a posthumous win for the Grammy Lifetime Achievement Award in 1972. His influence crossed musical genres, with inductions into the DownBeat Jazz Hall of Fame, the Rock and Roll Hall of Fame, and the National Rhythm & Blues Hall of Fame, among others.

Armstrong was born and raised in New Orleans. Coming to prominence in the 1920s as an inventive trumpet and cornet player, he was a foundational influence in jazz, shifting the focus of the music from collective improvisation to solo performance. Around 1922, Armstrong followed his mentor, Joe "King" Oliver, to Chicago to play in Oliver's Creole Jazz Band. Armstrong earned a reputation at "cutting contests", and his fame reached band leader Fletcher Henderson. Armstrong moved to New York City, where he became a featured and musically influential band soloist and recording artist. By the 1950s, Armstrong was an international musical icon, appearing regularly in radio and television broadcasts and on film. Apart from his music, he was also beloved as an entertainer, often joking with the audience and keeping a joyful public image at all times.

Armstrong's best known songs include "What a Wonderful World", "La Vie en Rose", "Hello, Dolly!", "On the Sunny Side of the Street", "Dream a Little Dream of Me", "When You're Smiling" and "When the Saints Go Marching In". He collaborated with Ella Fitzgerald, producing three records together: Ella and Louis (1956), Ella and Louis Again (1957), and Porgy and Bess (1959). He also appeared in films such as A Rhapsody in Black and Blue (1932), Cabin in the Sky (1943), High Society (1956), Paris Blues (1961), A Man Called Adam (1966), and Hello, Dolly! (1969).

With his instantly recognizable, rich, gravelly voice, Armstrong was also an influential singer and skillful improviser. He was also skilled at scat singing. By the end of Armstrong's life, his influence had spread to popular music. He was one of the first popular African-American entertainers to "cross over" to wide popularity with white and international audiences. Armstrong rarely publicly discussed racial issues, sometimes to the dismay of fellow black Americans, but took a well-publicized stand for desegregation in the Little Rock crisis. He could access the upper echelons of American society at a time when this was difficult for black men.