Millennium marked the band's return after 21 years to Warner Bros. Records. The album was also produced by EWF's founder and leader Maurice White.

Artists such as Prince and Ronnie Laws appeared on the LP.

• Maurice White – kalimba, percussion, lead vocals (1–3, 5–7, 9–15), backing vocals (1–3, 5–7, 9–15), drum programming (2), synth horn arrangements (6, 7), vocals (8, 12), arrangements (8, 14), horn arrangements (12)


• Sheldon Reynolds – keyboards, guitars, backing vocals (1–3, 5–7, 9–15), synth bass (1, 2), rhythm programming (1, 3, 5, 9, 13, 15), keyboard programming (2), synthesizer programming (2), drum programming (2, 10), additional programming (12), synthesizers (15)


• Michael McKnight – synthesizer programming (1–3, 5–7, 9–15), rhythm programming (1, 3, 9, 15), keyboard programming (2), keyboards (7), synth bass (7, 14), drum programming (7, 14), synth horn arrangements (7), arrangements (14), synthesizers (15)


• Freddie Ravel – synthesizers (5, 8), breath synthesizer solo (5, 8), synthesizer arrangements (5), drums (8), percussion sound design (8), arrangements (8),


• Darnell Spencer – synthesizer programming (6), synth bass (6), drum programming (6), rhythm arrangements (6)


• Rex Salas – keyboards (7), synthesizer programming (7), synth bass (7), drum programming (7), rhythm arrangements (7)


• Prince – keyboards (12), drum programming (12), backing vocals (12), rhythm arrangements (12)


• Dimitric Collins – drum programming (11, 14)


• Ralph Johnson – percussion


• James "Timbali" Cornwell – percussion (1, 9)


• Paulinho da Costa – percussion (2, 3, 5, 10, 13, 15), additional percussion (8)


• Verdine White – bass guitar


• Bill Meyers – keyboards (4, 16), acoustic piano (5), synthesizers (5, 11, 12, 15), rhythm programming (5), horn arrangements (5, 10, 12, 15), synth horn and string arrangements (11), acoustic piano solo (13), synth bass (15)


• Don Wyatt – keyboards (6, 11, 14), synth bass (11)


• Michael Thompson – guitars (1, 2, 5, 12, 14)


• Jorge Strunz – acoustic guitar (8)


• Nicky Brown – keyboards (1, 10), synthesizers (3, 15), rhythm arrangements (10)


• Burt Bacharach – additional keyboards (7)


• Claude Gaudette – additional keyboards (7)


• David Lawrence – keyboards (9), rhythm programming (9)
  Thom Bell – keyboards)14)


• Philip Bailey – backing vocals (1–3, 5–7, 9–15), lead vocals (3, 6, 7, 11, 13, 14), vocals (8, 12)


• Andrew Woolfolk – saxophones


• Gary Bias – saxophones


• Reggie C. Young – trombone


• Ray Brown – trumpet


• Frankie Blue – synthesizers (13), synthesizer programming (13), rhythm programming (13)


• Brad Cole – synthesizers (13)


• Dan Higgins – saxophones (1, 9, 12)


• Gerald Albright – saxophones (5, 7)


• Larry Williams – saxophones (12)


• Ronnie Laws – sax solo (15)


• Bill Reichenbach Jr. – trombone (1, 9, 12)


• Gary Grant – trumpet (1, 9, 12)


• Jerry Hey – trumpet (1, 9, 12), horn arrangements (1, 9)


• Michael "Patches" Stewart – trumpet (2, 3, 5, 10, 13, 15)


• Tom "Tom Tom 84" Washington – horn arrangements (2, 13)

Maurice White – producer (1–14, 16)
Freddie Ravel – producer (8)
Frankie Blue – producer (13)
Bill Meyers – producer (15)
Paul Klingberg – recording
Guy DeFazio – additional engineer
Ray Blair – assistant engineer
Mark Fergesen – assistant engineer
Judy Kirschner – assistant engineer
Keith Kresge – assistant engineer
Terry Reiff – assistant engineer
Lee Watters – assistant engineer
Mick Guzauski – mixing (1–3, 5, 7, 9–11, 13–15)
Vachik Aghanisntz – mixing (4, 8, 16)
Keith Cohen – mixing (6, 12)
Jeff Graham – mix assistant (1–3, 5, 7, 9–11, 13–15)
Anas Allaf – mix assistant (4, 8, 16)
Tommy Daugherty – mix assistant (6, 12)
Steve Hall – mastering at Future Disc (Hollywood, California)
Art Macnow – project supervisor
Richard Salvato – album coordinator
Reiko Yoshida – artwork coordinator
Kim Champagne – art direction
Tadanori Yokoo – illustration
Terushia Tajima – computer supervisor
Bob Cavallo – management