Darcy Aldridge – backing vocals (track 11)
Bobby Ross Avila – co-producer (tracks 10–13, 20); guitar (tracks 10–12); keyboards (tracks 11–13); piano (tracks 11, 20); backing vocals (track 11); additional drum programming (track 12); Moog Taurus (track 13); flute (track 20); Wurlitzer, scratches, and strings (track 10)
Dante "Destro" Barton – producer and additional engineering (track 12)
Jason Boyd – vocal producer (tracks 7, 9, 17)
Valdez Brantley – producer (track 8)
Bryan-Michael Cox – co-producer (tracks 4–6, 15, 21)
Larry Cox – additional keyboards (track 14)
Vincent Creusot – additional recording assistant (track 18)
Ian Cross – engineer (track 10), additional engineering (track 21)
Kevin "KD" Davis – engineer (track 16)
Vidal Davis – producer (tracks 7, 9, 17), mixing (tracks 7, 9)
Vince DiLorenzo – engineer (track 7, 9, 17)
Jermaine Dupri – producer (tracks 4–6, 15, 18, 21), mixing (tracks 4–6, 18, 21)
E Bass – guitar (track 3)
Blake Eisman – engineer (track 3, 19)
Faith Evans – additional backing vocals (track 9)
Brian Frye – engineer (tracks 4–6, 15, 18, 21)
John Frye – mixing (tracks 2, 19)
Richard Furch – mixing
Sean Garrett – vocal producer (tracks 2, 10), backing vocals (track 2)
Serban Ghenea– mixing (tracks 10–13, 17, 20)
John Hanes – additional Pro Tools engineer (tracks 10–13, 17, 20)
Andre Harris – producer (tracks 7, 9, 17), mixing (tracks 7, 9)
Rich Harrison – producer and instrumentation (track 16)
Delicia Hassan – production coordination (track 2)
John Horesco IV – engineer (tracks 4, 5, 21), mixing assistant (tracks 4–6, 15, 18, 21)
Jun Ishizeki – additional engineering (track 21)
IZ – co-producer and percussion (tracks 10–13, 20), drums (tracks 10, 11, 13, 20), bass (tracks 10, 13), guitar (tracks 10, 20), scratches (tracks 10, 12), Moog Taurus (track 10), keyboards (track 13)
Jadakiss – rap (track 3)
Jimmy Jam – producer (tracks 10–13, 20), Fender Rhodes (track 11)
LaMarquis Jefferson – bass (tracks 2, 9)
Just Blaze – producer (track 3)
Alicia Keys – vocals (track 18)
L-Roc – additional keyboards (track 2)
James Lackey – producer (track 1)
Ken Lewis – engineer, mixing, and guitar (track 3)
Terry Lewis – producer (tracks 10–13, 20)
Kelly "Dread" Liebelt – additional engineering (track 9)
Craig Love – guitar (track 19)
Ludacris – rap (track 2)
Kevin Mahoney – additional engineering (track 21)
Anthony Mandler – photography
Daniel Marino – guitar (track 12)
Matt Marrin – engineer (tracks 10–13, 20)
Manny Marroquin – mixing (track 14)
Tony Maserati – mixing (track 16)
Ann Mincieli – additional engineering (track 18)
Tadd Mingo – assistant engineer (tracks 4–6, 15, 18, 21)
Johnny "Natural" Najera – producer (track 8)
Paula Patton – backing vocals (track 14)
Herb Powers – mastering
Pro J – producer and instrumentation (track 14)
Edward Quesada – assistant engineer (track 4)
Mickael Rangeard – additional engineering (track 18)
Usher Raymond – executive producer, producer (tracks 1, 4, 8), lead vocals (all tracks), backing vocals (tracks 2, 10–14, 19, 20)
Tim Roberts – mixing assistant (tracks 10–13, 17, 20)
Donnie Scantz – engineer (track 2)
Manuel Seal – co-producer (track 18)
Shyne – rap (track 21)
Jon Smeltz – mixing (tracks 7, 9)
Jan Smith – vocal producer, vocal coach
Jonathan "Lil Jon" Smith – producer and mixing (track 2, 19), additional backing vocals (track 2)
Aaron Spears – producer (track 8)
Chris Steinmetz – additional engineering (track 21)
Patrice "ButtaPhly" Stewart – backing vocals (track 13)
Arthur "Buddy" Strong – producer (track 8)
Sean Tallman – assistant engineer (track 2)
Phil Tan – mixing (tracks 4–6, 15, 18, 21)
Robin Thicke – producer and instrumentation (track 14)
Ryan Toby – vocal producer (tracks 7, 9, 17)
Tony "Proof" Tolbert – backing vocals (tracks 10, 12, 20)
Twista – rap (track 21)
Mark Vinten – engineer (tracks 2, 19)
D.L. Warfield – layout design
Kanye West – rap (track 21)
Ryan West – engineer (track 3)
Doug Wilson – (track 21)
Stevie Wonder – harmonica (track 4)
Ghian Wright – assistant engineer (track 10)
James "Big Jim" Wright – co-producer (tracks 13, 20), bass (tracks 11, 20), Wurlitzer (track 13), keyboards (track 20)