Vo filme Firma hrajú Tom Cruise (Mitch McDeere), Jeanne Tripplehorn (Abby McDeere), Gene Hackman (Avery Tolar), Hal Holbrook (Oliver Lambert), Terry Kinney (Lamar Quinn), Wilford Brimley (William Devasher), Ed Harris (Wayne Tarrance), Holly Hunter (Tammy Hemphill), Karina Lombard (Young Woman on the Beach), David Strathairn (Ray McDeere), Gary Busey (Eddie Lomax), Steven Hill (F. Denton Voyles), Tobin Bell (The Nordic Man), Barbara Garrick (Kay Quinn), Jerry Hardin (Royce McKnight), Paul Calderon (Thomas Richie), Jerry Weintraub (Sonny Capps), Sullivan Walker (Thomas Abanks), Margo Martindale (Nina Huff), John Beal (Nathan Locke), Dean Norris (The Squat Man), Lou Walker (Frank Mulholland), Tommy Cresswell (Wally Hudson), David A. Kimball (Randall Dunbar), David Dwyer (Prison Guard), Afemo Omilami (Cotton Truck Driver), Clint Smith (Cotton Truck Driver), Jonathan Kaplan (Lawyer Recruiter), Paul Sorvino (Tommy Morolto (uncredited)), Joe Viterelli (Joey Morolto (uncredited)), Janie Paris (Madge), Susan Elliott (River Museum Guide), Erin Branham (River Museum Guide), Joey Anderson (Ruth), Deborah Thomas (Quinns' Maid), Rebecca Glenn (Young Woman at Patio Bar), Terri Welles (Woman Dancing with Avery), Chris Schadrack (Lawyer Recruiter), Jeffrey Buckner Ford (Lawyer Recruiter), Andy Armstrong (Bad Beach Man (uncredited)), Ron Clinton Smith (Cotton Truck Driver #1 (uncredited)), Julia Hayes (Girl in Bar (uncredited)), Yvonne Sayers (Young Girl (uncredited)).