From a young age, he began picking out songs on his sister's toy keyboard by ear until Frozine Francis, a proper piano teacher married to his uncle's father (and mother of popular movie composer Elvin Ross), started teaching him.
He has performed on stage with many notable artists such as Jon Batiste, Ziggy Modeliste, The Head and the Heart, My Morning Jacket, Arcade Fire, Dave Matthews Band, Corrine Bailey Rae, Chance the Rapper, The Revivalists, Nathaniel Rateliff and the Night Sweats, Hurray for the Riff Raff, José James, Dave Grohl, PJ Morton, Jimmy Buffett, Shovels & Rope, Robert Plant, Ivan Neville, Jupiter & Okwess, Pete Townshend, Amos Lee, Beck, Amanda Shaw, Trombone Shorty, Mannie Fresh, Cyril Neville, Robert Randolph of Robert Randolph and the Family Band, Allison Russell, Gary Clark Jr., George Porter Jr., Boyfriend (musician), Big Freedia, Pell, and Lauren Daigle.
[8] As a session musician, Roussel has worked with artists such as Irma Thomas, Tyler Perry, Ludwig Göransson, The Headhunters, Terence Blanchard, Preservation Hall Jazz Band, John Boutté, Donald Harrison, Jr., Herlin Riley, Victor Goines, Glen David Andrews, Roland Guerin, Khris Royal, Ivan Neville, George Porter Jr., Jamison Ross, Cedric Burnside, PJ Morton, Big Freedia, The Soul Rebels, Curren$y, Mannie Fresh, Quiana Lynell.
[13] The album features Shannon Powell, Weedie Braimah, Bill Summers, Alvin Ford, Alexey Marti, Roland Guerin, DJ Raymond, and Darryl McCoy Jr.[14] His second album as a leader (NOLA à la Mode) was released in 2023 in a solo piano format featuring songs by New Orleans legends James Booker, Professor Longhair, Allen Toussaint, Dr. John, Jelly Roll Morton, and Harold Battiste along with a handful of original compositions.
[15] Roussel's third album, Church of New Orleans, was released on January 24, 2025, and features special guests such as Irma Thomas, Ivan Neville, Preservation Hall Jazz Band, and John Boutte.