Stashwick was born in Chicago, Illinois, and raised in the suburbs right outside of the city. Soon after graduating from Illinois State University, he began performing at several local improvisational theaters and was quickly hired to tour with "The Second City" all over the country. Following productions at The Second City Detroit and The Second City Northwest, he moved to New York. Todd was up for Saturday Night Live the same year that fellow Second City Alumni David Koechner joined the cast. While in New York, he formed a company of improvisers and began staging the underground critically acclaimed Burn Manhattan all over the city under the direction of Shira Piven.[who?] Work in television and film drew him to Los Angeles where he shot several pilots and series including recurring work on the series M.D.s, American Dreams, Rodney and Still Standing. Stashwick has had several guest-starring roles in numerous television shows, (see "Filmography" section below). He had a significant supporting role on The Riches playing Minnie Driver's nefarious cousin Dale until its cancellation in September 2008.
Todd is also the co-creator, along with DC and Marvel artist Dennis Calero of the online web comic Devil Inside, which had its launch at the 2010 San Diego Comic-Con. Todd and Dennis met because Dennis had drawn Todd's character from Heroes into the Heroes online comic. The two decided to collaborate on their own title which is being self-published once a week in traditional serialized strip form on Todd's personal website, for free. Devil Inside tells the story of Jack Springheel. aka The Devil, who has a crisis of conscience. He blasts out of hell and lands in the Nevada desert. He does not want to go back, he wants to quit. But there are forces conspiring to drag him back to hell. If he doesn't use his mojo he stays off the grid and they can't find him. But he is the Devil after all and old habits die hard, not using his powers proves more difficult than he thought. A man caught between what he is and what he wants to be. He's trying to stay one step ahead of his adversaries. Todd and Dennis Calero are in development with the Syfy channel with their pilot Clandestine. The two will develop and write the pilot script for the swashbuckling space adventure/drama. The two will also serve as co-executive producers. John Shiban will serve as script supervisor. Stashwick is co-writing, with Amy Hennig, an as yet unnamed Star Wars video game for Visceral Games and Electronic Arts.