James McAvoy as Patricia / Dennis / Hedwig / The Beast / Barry / Heinrich / Jade / Ian / Mary Reynolds / Norma / Jalin / Kat / B.T. / Kevin Wendell Crumb / Mr. Pritchard / Felida / Luke / Goddard / Samuel / Polly

Bruce Willis as David Dunn / The Overseer

Samuel L. Jackson as Elijah Price / Mr. Glass

Sarah Paulson as Dr. Ellie Staple

Anya Taylor-Joy as Casey Cooke

Spencer Treat Clark as Joseph Dunn

Charlayne Woodard as Mrs. Price

Luke Kirby as Pierce

Adam David Thompson as Daryl

M. Night Shyamalan as Jai, Security Guard

Shannon Destiny Ryan as Cheerleading Girl

Diana Silvers as Cheerleading Girl

Nina Wisner as Cheerleading Girl

Kyli Zion as Cheerleading Girl

Serge Didenko as Ronald, Powerful Young Man

Russell Posner as T, Skinny Camera Kid

Kimberly S. Fairbanks as Assistant Principal

Rosemary Howard as Penelope Crumb

Bryan McElroy as Clarence Crumb

Owen Vitullo as Young Kevin

William Turner as Young Elijah

Johnny Hiram Jamison as Thirteen Year-Old Elijah (archive footage)

Leslie Stefanson as Woman on Train

Marc H. Glick as Train Engineer

Brick Mason as Carnival Barker

Bostin Christopher as Comic Book Counter Guy

Ukee Washington as News Anchor

Colin Becker as Ten Year-Old David

Brian Anthony Wilson as Security Guard in Car

Tobias Segal as Surveillance Security Guard

Joseph Thuet as Joe, Security Guard

Tatiana St. Phard as Woman Group Member

Tom DiNardo as Homeless Person

Timothy Chivalette as Comic Book Geek

Jack McCafferty as Comic Book Geek

Darby Schlosser as Foster Sibling

Jordan Coker as Foster Sibling

Emma Hong as Foster Sibling

Xaiver Gerald as Foster Sibling

Tim Duquette as Patient Jimmy

Nathan Nauroth as Orderly Harrison

Ana Leonard as Hospital Volunteer

Elijah Davis as Maintenance worker (uncredited)

Charles W Harris III as Officer Williams (uncredited)

Jesse Ridgway as College Student (uncredited)

Aaron Bartuska as Student (uncredited)

Jane Justice Park as Korean Mother (uncredited)

Jesse Bradley as Passerby