 | Grace VanderWaal als Susan "Stargirl" Caraway |
 | Graham Verchere als Leo Borlock |
 | Karan Brar als Kevin Singh |
 | Maximiliano Hernández als Mr. Robineau |
 | Darby Stanchfield als Gloria Borlock |
 | Giancarlo Esposito als Archie Brubaker |
 | Collin Blackford als Benny Burrito |
 | Annacheska Brown als Tess Reed |
 | Shelby Simmons als Hillari Kimble |
 | Allison Wentworth als Dori Dilson |
 | Juliocesar Chavez als Alan Ferko |
 | Artemis als Mallory Franklin |
| Julia Flores als Summer |
 | Gabriella Surodjawan als Kim |
 | John Apolinar als Wayne Parnell |
 | Alex James als Zack James |
 | Enzo De Angelis als Leo Age 8 |
| Cayman Guay als Cool Girl |
 | Sara Arrington als Ana Caraway |
 | Lucinda Marker als Principal Sutters |
 | Hannah Kauffmann als Band Leader |
 | Gavin White als Big Kid #1 |
| Sean Dennis als Big Kid #2 |
| David Trujillo als Big Kid #3 |
 | Troy Brookins als Ron Kovac |
 | Ryan Begay als Mud Frog Fan |
 | Damian O'Hare als Leo's Dad |
| Audra Charity als Emcee |
| Atharva Verma als Kevin Age 8 |
| Jimmy E. Jones als Teacher |
 | Orion Carrington als Young Male Teacher |
| Tom Sons als EMT |
| Eric Archuleta als Athletic Trainer |
| Rebecca Ann Arscott als Keyboard Player: Winter Dance Band |
| Herve Gaspard als Lead Singer / Guitar: Winter Dance Band |
| Paul Palmer III als Drummer: Winter Dance Band |
| Artha Meadors als Bass: Winter Dance Band |
| Armando Arellano als Mudfrogs Marching Band |
| Victor Armijo als Mudfrogs Marching Band |
| Andrew Blair als Mudfrogs Marching Band |
| Vincent Conte als Mudfrogs Marching Band |
| Giselle Gruz als Mudfrogs Marching Band |
| Oscar Gamboa als Mudfrogs Marching Band |
| Edgar Hernandez als Mudfrogs Marching Band |
| Gabe Hicks als Mudfrogs Marching Band |
| Chris Kingswadd als Mudfrogs Marching Band |
| Shannon Latham als Mudfrogs Marching Band |
| Julio Quiroz Lopez als Mudfrogs Marching Band |
| Spenser Lotz als Mudfrogs Marching Band |
| Gus Pedrotty als Mudfrogs Marching Band |
| Isiah Rojas als Mudfrogs Marching Band |
| Alla Shapiro als Mudfrogs Marching Band |
| Jeanette Silva als Mudfrogs Marching Band |
| Kayla Strickler als Mudfrogs Marching Band |
| David Hight als Speech Competition Attendee / Ball Game Attendee (uncredited) |
| Jesse Mattson als Football Player (uncredited) |
 | J. Nathan Simmons als Fan (uncredited) |
| Michael E. Stogner als Fan (uncredited) |
| Ian Willoughby als Football Player (uncredited) |
 | Shylo Molina als Talent Show Magician (uncredited) |
 | Alexander Alayon Jr. als High Schooler (uncredited) |
| Braden Wilcox als High School Student (uncredited) |
| Julia Hart | Director |
| Jerry Spinelli | Novel |
| Ellen Goldsmith-Vein | Producer |
| Kristin Hahn | Producer |
| Jordan Horowitz | Executive Producer |
| James Powers | Executive Producer |
| Jon Levin | Executive Producer |
| Lee Stollman | Producer |
| Rob Simonsen | Original Music Composer |
| Shayar Bhansali | Editor |
| Tracey Wadmore-Smith | Editor |
| Gae S. Buckley | Production Design |
| Natalie O'Brien | Costume Design |
| Randi Hiller | Casting |
| Ian Scroggins | Art Direction |
| Patrick Cassidy | Set Decoration |
| Kristin Hahn | Screenplay |
| Julia Hart | Screenplay |
| Jerry Spinelli | Executive Producer |
| Catherine Hardwicke | Executive Producer |
| Eddie Gamarra | Executive Producer |
| Bryce Fortner | Director of Photography |
| Mandy Moore | Choreographer |
| Brittany N. Grooms | Casting |
| James Powers | Unit Production Manager |
| Kaaren F. Ochoa | First Assistant Director |
| Amanda Luce | Second Assistant Director |
| Ed Duran | Stunt Coordinator |
| Ryan Staats | Stunt Coordinator |
| Mark Robert Ellis | Stunt Coordinator |
| Jermaine Washington | Stunt Coordinator |
| Mycah Huitron | Stunt Double |
| Roland Bruno | Stunt Double |
| Maurice Woodard | Utility Stunts |
| Jayson Serda | Utility Stunts |
| Kenneth Maxwell | Stunts |
| Hayleigh Patterson | Stunts |
| Finnly Smathers | Stunts |
| Matthew Joseph Smith | Stunts |
| Jimmy Joseph Genovesi | Stunts |
| Briana Bri Morrison | Stunts |
| Daniel Huynh | Stunts |
| Kimberly White | Stunts |
| Gerardo Sandoval | Stunts |
| Briana Collins | Stunts |
| Rob Corlew | Production Supervisor |
| Elizabeth Flaherty | Assistant Art Director |
| Adrian Segura | Leadman |
| Lenka Padysakova | Assistant Costume Designer |
| Shaun Garcia | Costume Supervisor |
| Katie L. Murphy | Key Costumer |
| Lisa McWhorter | Set Costumer |
| Diane Metzler | Set Costumer |
| Mary Bowman | Set Costumer |
| Kate Czark | Set Costumer |
| Michael Klepacki | Set Costumer |
| Ryan Holler | Set Costumer |
| Erin Nielsen | Set Costumer |
| Tiffany Rink | Set Costumer |
| Jilli Oyenque | Seamstress |
| Nichol Kim | Costume Assistant |
| Ashlynne Padilla | Makeup Department Head |
| Ashley Moore | Key Makeup Artist |
| Yael Rosas | Assistant Makeup Artist |
| Chase Heard | Hair Department Head |
| Janessa Bouldin | Key Hair Stylist |
| Yvette Meely | Assistant Hairstylist |
| Laura Jean Bransky | Script Supervisor |
| Matt Harshbarger | Steadicam Operator |
| Matt Harshbarger | "A" Camera Operator |
| Gabriel Pfeiffer | First Assistant "A" Camera |
| John Hamilton | Second Assistant "A" Camera |
| Liza Bambenek | First Assistant "B" Camera |
| Artu Arin | Second Assistant "B" Camera |
| Tim Gregoire | Digital Imaging Technician |
| Taylor Hilburn | Camera Loader |
| Darryl L. Frank | Sound Mixer |
| David Sickles | Boom Operator |
| Deborah Wakshull | Location Manager |
| Cristal Jones | Assistant Location Manager |
| Ben Roe | Assistant Location Manager |
| Jeffrey Harlacker | Associate Producer |
| Lauren Clark Carroll | First Assistant Editor |
| Mildred Iatrou | Supervising Sound Editor |
| Doug Jackson | Supervising Sound Editor |
| Teri E. Dorman | Supervising Dialogue Editor |
| Galen Goodpaster | ADR Editor |
| Melissa Lytle | Assistant Sound Editor |
| Terry Wilson | Music Editor |
| Goro Koyama | Foley Artist |
| Sandra Fox | Foley Artist |
| Andy Malcolm | Foley Artist |
| Davi Aquino | Foley Recordist |
| Chelsea Body | Foley Recordist |
| Jenna Dalla Riva | Foley Recordist |
| Andy Hay | Sound Re-Recording Mixer |
| Samuel R. Green | Sound Engineer |
| Julian Slater | Sound Re-Recording Mixer |
| Geoff Ethridge | Sound Engineer |
| Jesse Johnstone | Sound Recordist |
| Neil Solberg | Chief Lighting Technician |
| Hannes Harmon | Best Boy Electric |
| Dwight Dollins | Key Grip |
| Anthony Bartra | Best Boy Grip |
| Ian Hanna | Dolly Grip |
| Eli Schneider | Dolly Grip |
| Robert Lofstrom | Rigging Gaffer |
| Erik Hernandez | Rigging Gaffer |
| Forrest A. Haag | Property Master |
| Joshua R. Aragon | Assistant Property Master |
| David Greene | Special Effects Supervisor |
| Fagan O'Reilly | Special Effects Coordinator |
| Jon Shroyer | Special Effects Technician |
| Chance Romero | Production Coordinator |
| Whitney Guaderrama | Production Secretary |
| Dustin DellaVecchia | Travel Coordinator |
| Bryan Benning | Assistant Production Coordinator |
| Arlen Johnson | Construction Coordinator |
| Tamra Scott | Graphic Designer |
| Claire LaRose | Producer's Assistant |
| Alicia Castro Chicol | Art Department Coordinator |
| Kerry Newberry | Production Accountant |
| Marisa Frantz | Set Designer |
| Sarah Iha | Art Department Assistant |
| Travis Lathrop | Standby Painter |
| Kelly M. Stone | First Assistant Accountant |
| Jean E. Jacobson | Payroll Accountant |
| Wolf Schneider | Unit Publicist |
| Dale Robinette | Still Photographer |
| Kiira Arai | Local Casting |
| Sande Alessi | Extras Casting |
| Patrick A. Reynolds Jr. | Transportation Coordinator |
| Jared Meador | Transportation Captain |
| Dave Calaway | Transportation Captain |
| James William Ray | Transportation Captain |
| Gretchen Heath | Casting Assistant |
| Raven Midkiff | Visual Effects Coordinator |
| Joey Bonander | Visual Effects Producer |
| Jill Bogdanowicz | Colorist |
| Jordan Horowitz | Screenplay |
