Nathan Fillion Richard Castle Actor Stana Katic NYPD Captain Kate Beckett Actor Susan Sullivan Martha Rodgers Actor Molly C. Quinn Alexis Castle Actor Ruben Santiago-Hudson Captain Roy Montgomery Actor Tamala Jones Lanie Parish Actor Jon Huertas NYPD Detective Javier Esposito Actor Seamus Dever NYPD Detective Kevin Ryan Actor Gary Basaraba Guest Star Peter Onorati Guest Star John Ciccolini Guest Star Joe Guzaldo Guest Star Liz Vassey Guest Star Gregg Daniel Guest Star Darin Brooks Guest Star Beth Behrs Guest Star Alton Clemente Guest Star Stephan Smith Collins Guest Star Andrew W. Marlowe Executive Producer Rob Bowman Executive Producer Laurie Zaks Executive Producer David Amann Executive Producer Scott Williams Writer Steve Boyum Director