Sheila Jordan was born Sheila Jeanette Dawson on November 18, 1928, in Detroit, Michigan. Her father left soon after her birth and her mother struggled with alcoholism, so Jordan was raised largely by her maternal grandparents in Summerhill, Pennsylvania, a coal-mining town she later described as among the poorest in a poor region. She returned to the Detroit area as a teenager in the early 1940s and started performing in clubs almost immediately, drawn into the city's postwar bebop scene. There she teamed with two young men, Skeeter Spight and Leroy Mitchell, to form a vocal trio called Skeeter, Mitch and Jean (Jordan was "Jean"), which set lyrics to Charlie Parker's recorded solos and sang them in three-part harmony, a vocalese approach that predated Lambert, Hendricks and Ross by roughly a decade, though the trio itself never recorded. Jordan met Parker in person at his Detroit dates, and he began inviting the group to sit in; he later told her directly, "You've got million dollar ears, kid," a line that stuck to her for the rest of her career and that she credited as the moment she committed her life to jazz.

She moved to New York in 1951 and studied music theory with Lennie Tristano and briefly with Charles Mingus, immersing herself further in Parker's vocabulary. In 1952 she married the bebop pianist Duke Jordan, one of Parker's own regular sidemen; the marriage lasted a decade, ending in divorce in 1962, and produced a daughter, Tracey. Jordan continued working New York's jazz rooms through the 1950s while her husband's heroin addiction worsened, and by her own account she leaned harder into a day job, first as a typist and later for two decades as a legal secretary at a Madison Avenue advertising agency, to support herself and her daughter.

Her breakthrough as a recording artist came almost by accident. Ruth Lion, wife of Blue Note Records co-founder Alfred Lion and herself a singer, heard Jordan performing at the Page Three, a Greenwich Village club, and urged her husband to come listen. Blue Note had never before recorded a jazz vocalist as a policy matter, but Lion made an exception, and on September 19 and October 12, 1962, at Rudy Van Gelder's Englewood Cliffs studio, Jordan recorded Portrait of Sheila with guitarist Barry Galbraith, bassist Steve Swallow and drummer Denzil Best. Released by Blue Note in January 1963 with liner notes by Nat Hentoff, it remains one of the small handful of vocal albums the label issued in its history. Jordan originally wanted the record built entirely around bass and voice; Blue Note turned the idea down, though she would spend much of the next two decades making exactly that record, again and again, for other labels. Portrait of Sheila won her the top spot in DownBeat's 1963 Critics Poll for Talent Deserving Wider Recognition, but she did not lead another studio session for over a decade, continuing to work day jobs while raising her daughter and performing only sporadically.

Jordan's return to regular recording began with Confirmation (East Wind, 1975), cut in New York with bassist Cameron Brown, drummer Beaver Harris, pianist Alan Pasqua and saxophonist Norman Marnell. Two years later, in Oslo, she made Sheila (SteepleChase, 1978) with Norwegian bassist Arild Andersen alone, a stripped-to-the-bone reading of standards by Billy Strayhorn, Steve Kuhn and others that became the first fully realized version of the bass-and-voice duo format Blue Note had rejected fifteen years earlier. She carried that format forward through the 1980s and beyond with bassist Harvie S (recording then as Harvie Swartz), the longest of her duo partnerships, on Old Time Feeling (recorded 1982, reissued on Muse in 1989) and Songs From Within (MA Recordings, 1993); she also worked through the era as the vocalist in pianist Steve Kuhn's quartet, appearing on the ECM album Playground (recorded 1979, released 1980) alongside Kuhn, Harvie Swartz and drummer Bob Moses. In 1974 she began teaching as an artist-in-residence at the City College of New York, and from 1978 to 2005 she held a regular faculty position there running vocal jazz workshops, alongside guest teaching stints at the University of Massachusetts Amherst, the Vermont Jazz Center, and her own Jazz Camps and workshops internationally; she was laid off from her advertising-agency job in 1987 and, with her daughter grown, turned to music and teaching full time.

Her later leader catalog, recorded almost entirely for small independent labels, includes Jazz Child (HighNote, 1999), a studio reunion with Steve Kuhn's trio (bassist David Finck, drummer Billy Drummond) and guest vocalist Theo Bleckmann; Little Song (HighNote, 2003); and Celebration (HighNote, 2005), a duo album with bassist Cameron Brown recorded live at the Triad in Manhattan on her 76th birthday in November 2004. She received the Mary Lou Williams Award for a lifetime of service to jazz in 2008 and was named a National Endowment for the Arts Jazz Master in 2012, the highest official honor bestowed on a jazz musician in the United States, cited for both her singing and her decades of teaching. She continued performing into her nineties, working steadily with bassist Cameron Brown and, in her final years, with guitarist Roni Ben-Hur and Harvie S. That trio recorded Portrait Now at RVS Studio in the Bronx in 2022, a set that answers her Blue Note debut sixty years on and shares repertoire with it; Harvie S recorded, produced and mixed the album, and Ben-Hur played guitar alongside his bass, the two of them her only accompanists. Dot Time Records released it on February 14, 2025, the same day Jordan gave her final live performance, at the Green Mill in Chicago. She died on August 11, 2025, at her apartment in Manhattan, at age 96, passing in her sleep while her friend Joan Belgrave, widow of trumpeter Marcus Belgrave, played her a recording of one of his compositions.

Jordan sang almost entirely inside the vocabulary of bebop, treating her voice as an improvising horn rather than a melody-first instrument: she scatted with the harmonic daring of a saxophonist working through a Charlie Parker line, took liberties with tempo and phrasing on nearly every performance, and favored dissonant intervals and minor-key standards that most vocalists of her generation avoided. That approach made her, in critic Scott Yanow's phrase, "one of the most consistently creative of all jazz singers," prized by critics and by generations of younger singers even though it kept her outside the commercial mainstream for most of her career. Her most lasting technical contribution was the vocal-bass duo format: turned down by Blue Note in 1962, she built it herself over the following decades with Arild Andersen, Harvie S and Cameron Brown, stripping her singing down to a single bass line with nothing to hide behind, a format now closely associated with her name and adopted by many singers who came after her. Her teaching, thirty-one years at City College of New York plus decades of international workshops, extended that same emphasis on risk and personal voice to generations of vocal students rather than to a working band of alumni, the model closer to a conservatory practice than to a bandstand apprenticeship.