Josh Radnor Ted Mosby Actor Jason Segel Marshall Erikson Actor Neil Patrick Harris Barney Stinson Actor Alyson Hannigan Lily Aldrin Actor Cobie Smulders Robin Sherbatsky Actor Bob Saget Narrator Charlene Amoia Wendy Guest Star Bryan Callen Bilson Guest Star Laura Prepon Karen Guest Star Rowly Dennis Trevor Guest Star Hayes MacArthur Curt 'Ironman' Irons Guest Star Koby Rouviere 8-Year Old Marshall Guest Star Laura Ann Kesling 8-Year Old Nicole Guest Star Houston Rhines Jerry Guest Star David Burtka Scooter Guest Star Patrick Moote Darren Guest Star Taran Killam Gary Blauman Guest Star Carter Bays Executive Producer Craig Thomas Executive Producer Craig Gerard Writer Matthew Zinman Writer Pamela Fryman Director