Wood made his film debut with a small part in Back to the Future Part II (1989). He went on to achieve recognition as a child actor with multiple roles such as Avalon (1990) and The Good Son (1993). As a teenager, he starred in several films including North (1994), Flipper (1996), and The Ice Storm (1997). Following the success of The Lord of the Rings, Wood has appeared in a wide range of films, including Eternal Sunshine of the Spotless Mind (2004), Paris, je t'aime (2006), and I Don't Feel at Home in This World Anymore (2017).
Wood's voice roles include Mumble in the Happy Feet film franchise (2006β2011), the title protagonist in 9 (2009), Spyro the Dragon in the Legend of Spyro video game trilogy (2006β2008), Beck on Disney XD's Tron: Uprising (2012β2013), Sigma in Season 10 of Red vs. Blue, and Wirt in the Cartoon Network miniseries Over the Garden Wall (2014). He played Ryan Newman on the FX dark comedy series Wilfred (2011β2014), for which he received a Satellite Award nomination for Best Actor, and Todd Brotzman in the BBC America series Dirk Gently's Holistic Detective Agency (2016β2017).