David Hornsby is an American actor and writer best known for his roles in the television series The Joe Schmo Show (2003) and Jake in Progress (2005-2006).
He has served as a writer, supervising producer, and story editor on It's Always Sunny in Philadelphia since 2005, on which he has a recurring role as Matthew Mara, more popularly known as "Rickety Cricket."
Other television series he has acted in include ER, Six Feet Under, The Mullets, Threshold, The West Wing, The Unit and Dirt.
He also had a starring role in the animated comedy series Unsupervised, in 2012.
He also created and starred in the short-lived sitcom How to Be a Gentleman, which aired in the USA from 2011-2012.
He has also appeared in numerous feature films including Pearl Harbor (2001), Minority Report (2002), Christmas with the Kranks (2004), Flags of Our Fathers (2006) and AVPR: Aliens vs Predator - Requiem (2007).
He is married to actress Emily Deschanel.