Jumaane Smith grew up in Seattle in a household marked by abuse, with a stepfather struggling with drug addiction; he and his mother eventually left the situation after nearly a decade. He has said music found him at that time and effectively saved him. He picked up trumpet around age nine after a school music teacher redirected him from French horn (there weren't enough horns to go around), and he threw himself into practicing, often outdoors so as not to wear on his mother's ears. At Roosevelt High School he spent all four years in the jazz program under director Scott Brown, toured Europe with the school's jazz band at 16, and won the outstanding soloist trumpet award at the Essentially Ellington High School Jazz Band Competition & Festival at Lincoln Center.

Smith initially accepted a scholarship to New School University in New York, where trumpeter and bandleader Wynton Marsalis heard him and encouraged the move east. Marsalis then invited him into the inaugural class of Juilliard's newly launched Jazz Studies program in 2001, one of only seventeen musicians selected (four of them trumpeters), and gave him private lessons, something Marsalis rarely did for students. During his four years at Juilliard, Smith led the trumpet section of the school's first Jazz Orchestra and played in its Jazz Quintet. It was also in New York, while he was headlining his own first gig in the city, that he met drummer Rashied Ali, who happened to live nearby; Ali, who had been John Coltrane's own last drummer, became a mentor and, in Smith's telling, a father figure. The relationship became a working one as well as a personal one: Smith is the trumpeter on both volumes of Judgment Day, the reconstituted Rashied Ali Quintet's session recorded February 17-18, 2005, at Ali's own Survival Studios in New York, alongside pianist Greg Murphy, bassist Joris Teepe, and tenor saxophonist Lawrence Clark.

In 2005 Smith joined Michael Buble's touring and recording band as lead trumpeter and vocalist, a relationship that has now run more than eighteen years and includes appearances on five Grammy-winning Buble albums that have collectively sold upwards of sixty million copies, plus two Emmy-nominated television specials. Through that work and beyond it he has performed at the Grammy Awards alongside Stevie Wonder, played a trumpet-soloist acting role in Steven Spielberg's 2021 film of West Side Story, and appeared at the White House and on the Today Show, the Tonight Show, Oprah, Good Morning America, and American Idol. He was also a member of Harry Connick Jr.'s house band for the syndicated daytime program Harry, and served as featured soloist on singer Jackie Evancho's Songs of the Silver Screen tour, backed by a sixty-piece orchestra.

Alongside the touring work, Smith built a session and studio career of his own, recording as a horn player and occasional backing vocalist for artists including Alicia Keys, Quincy Jones, Herbie Hancock, Aretha Franklin, and Van Morrison, and released his own debut album as a leader, I Only Have Eyes for You, in 2014, featuring guest turns from Michael Buble, Jackie Evancho, and the vocal group Naturally 7. A second album, When You're Smiling, followed in January 2020.

His third album, Come On Home, released August 16, 2024, on Zinn Music, marked a turn toward original composition and autobiography: mostly Smith's own songs, tracing the childhood abuse he had lived through and framing the record, in his words, as a personal and redeeming homecoming after nearly two decades as someone else's sideman. DownBeat gave it four stars, and it spent twelve consecutive weeks in the JazzWeek chart's top 50. Smith continues to tour internationally with his own quintet, at rooms including Jazz at Lincoln Center, Birdland, Ronnie Scott's, and Ravinia, while remaining active with Buble's band.

Smith's playing sits squarely in a hard-swinging, vocally inflected mainstream tradition; he has named trombonist J.J. Johnson and trumpeter Freddie Hubbard as formative influences, and his own singing, developed alongside his horn playing rather than as an afterthought, lets him work equally as a trumpet soloist and a vocalist on the same bandstand. That dual skill set, sharpened under Wynton Marsalis at Juilliard and tested nightly across nearly two decades in Michael Buble's band, made him equally credible in classic-songbook jazz, pop-facing crossover material, and R&B and gospel-adjacent session work. Come On Home pushed that range toward original songwriting for the first time, drawing comparisons in the press to Sam Cooke and Louis Armstrong for the way it blends jazz phrasing with soul and blues feeling.