Rossano Sportiello was born in Vigevano, in Lombardy, on June 1, 1974. He started piano at nine under the Italian classical pianist Carlo Villa and stayed on that track all the way through a conservatory degree in classical piano, taken in 1996. The jazz work started long before the diploma: he was playing professionally in clubs around Milan at sixteen, and in 1992 he joined the Milano Jazz Gang, a long-running Italian traditional-jazz band, touring Italy and western Europe with it until the end of 2000.

The year the Milano Jazz Gang chapter closed was also the year he met Barry Harris, who became his mentor and, in the sentence every write-up of Sportiello since has quoted, called him "the best stride piano player" he had ever heard. Trombonist and arranger Dan Barrett was the other decisive contact. Barrett brought Sportiello forward as a soloist inside the eight-piece all-star American band he led at the 2002 Ascona Jazz Festival in Switzerland, which is where the international swing-party circuit first heard him. He has returned to Ascona repeatedly, and at the festival's twenty-fifth anniversary in 2009 he was given the Ascona Jazz Award, cited specifically for his stride playing. His first trip to the United States came in 2003, at the invitation of Mat Domber of Arbors Records, to play the label's "March of Jazz" party in Clearwater Beach, Florida. Following his 2007 marriage to the American writer Lala Moore, he settled in New York City.

Arbors became his main recorded home and has stayed so for two decades. The solo record Heart and Soul, cut July 12, 2005 at the Old Church in Boswil, Switzerland and issued in 2006, was picked by the French magazine Jazz Classique among its ten best of the year. People Will Say We're In Love (2007), the first of two duo albums with the Australian bassist and singer Nicki Parrott, was named by The New Yorker one of the ten best jazz CDs of 2007; Do It Again, recorded in New York on March 4 and 5, 2009, followed. In 2010 the label gave him volume 22 of its Arbors Piano Series for Lucky to Be Me, a trio date with bassist Frank Tate and drummer Dennis Mackrel taped at Nola Studios on April 20 and 21, 2010. Volume 21 of the same series, released the same year, had gone to Ehud Asherie.

Two long-running working bands have carried most of his touring since 2008. One is the quartet of tenor saxophonist Harry Allen, with whom he also cut two songbook duo and trio records for GAC, Conversations: The Johnny Burke Songbook (2011) and I Walk With Music: The Hoagy Carmichael Songbook (recorded January 9, 2013 at Trading 8s in Paramus, New Jersey). The other is the Three Wise Men, the European trio led by the Dutch reedman Frank Roberscheuten with Viennese vibraphonist and drummer Martin Breinschmid, a group Sportiello counts at more than 500 concerts across its first twelve years. In parallel he has led a standing trio with Nicki Parrott and drummer Eddie Metz Jr. through Live at the Jazz Corner (2012, liner notes by Terry Teachout), It's a Good Day and Strictly Confidential (recorded October 5 and 6, 2015 at Avatar Studios in New York), and he has been tenor saxophonist Scott Hamilton's pianist of choice on Midnight at Nola's Penthouse (2010), Live at Smalls (2014) and Live at Pyatt Hall, taped in Vancouver on July 2, 2017.

The widest audience for his playing came from a screen. Sportiello was one of four pianists credited for the piano tracks on Boardwalk Empire Volume 1: Music from the HBO Original Series (Elektra, 2011), alongside Ehud Asherie, Mark Shane and Peter Mintun; the album took the 2012 Grammy for Best Compilation Soundtrack for Visual Media. He played the Newport Jazz Festival on July 31, 2016 as a solo pianist, invited by George Wein, and has worked New York rooms as different as Carnegie Hall, the Blue Note, Birdland, the Café Carlyle, the 92nd Street Y, Smalls and Mezzrow. The honors have come from three countries: the Académie du Jazz's Prix du Jazz Classique in France for the 2005 solo album Piano on My Mind, the Ascona award in Switzerland in 2009, and, on May 4, 2011, the Premio Vittorio Ramella, given in Vigevano to natives of the town who have distinguished themselves internationally. He has lectured and given masterclasses at the University of Toronto's jazz studies program, the University of Central Florida, Claremont College in California and St John's College, Cambridge.

The classical training never got put away. Between 2010 and 2011 he made three albums for the Japanese SwingBros label built entirely on classical repertoire played as jazz: Chopin in Jazz, Schubert in Jazz and Liszt in Jazz. The habit shows up inside the jazz records too, as when Lucky to Be Me closes on Bach's Prelude No. 14 in F sharp minor from Book II of the Well-Tempered Clavier. His unaccompanied catalog runs from In the Dark (Sackville) through Piano on My Mind, It Amazes Me (Sackville, 2009), Pastel (recorded in New York on December 10, 2016) and That's It! (recorded July 23 and 24, 2020), the last of these carrying liner notes by three of his elders at once: Barry Harris, Dick Hyman and Terry Gibbs. During the pandemic he streamed more than a hundred weekly concerts from his New York apartment, and in 2024 the San Diego Jazz Party gave him its Jazz Legend Award.

Sportiello is that comparatively rare thing in the current scene, a player whose primary language is stride and Harlem piano rather than bebop, held together by a conservatory technique he uses for control rather than display. Critics have placed him in a line from Ralph Sutton and Dave McKenna, and he has named Ralph Sutton his "spiritual father"; he cites Barry Harris, Hank Jones and Tommy Flanagan as the models for touch, crediting Jones with the lesson that you do not have to hit the instrument hard to swing, and he draws openly on Fats Waller, Teddy Wilson, Art Tatum, Earl Hines, Ellis Larkins and Bill Evans. Reviewing That's It! for The Syncopated Times in January 2021, Scott Yanow described the record as having "the relaxed informality of that type of solo recital, one that is full of brilliance," and singled out an original of Sportiello's that "sounds like a lost standard of the 1930s." The stride vocabulary he inherited from the James P. Johnson and Waller line is what got him the Ascona award and the Barry Harris endorsement, but the programs he actually plays reach from Bach preludes to the Great American Songbook to his own writing.