He began his career in the 1980s, working as a voice artist on the satirical puppet show Spitting Image. In the early 1990s, he began creating original comic characters; this led him to win the Perrier Award at the Edinburgh Festival Fringe. In 1999, he co-founded the production company Baby Cow Productions.
While working with Armando Iannucci on The Day Today and On the Hour, Coogan created his most developed and popular character, Alan Partridge, a socially awkward and politically incorrect regional media personality. He featured in several television series, which earned Coogan three BAFTA nominations and two wins for Best Comedy Performance. A feature-length film, Alan Partridge: Alpha Papa, was released in 2013, and opened at number one at the British box office.
Coogan grew in prominence within the film industry in 2002, after starring in The Parole Officer and 24 Hour Party People. He portrayed Phileas Fogg in the 2004 remake Around the World in 80 Days, and has co-starred in The Other Guys, Tropic Thunder, In the Loop, Hamlet 2, Our Idiot Brother, Ruby Sparks and the Night at the Museum films, as well as collaborating with Rob Brydon in The Trip and Tristram Shandy: A Cock and Bull Story. He was also a principal voice actor in the computer animated comedy Despicable Me 2.
Coogan has also branched out into more dramatic roles, with What Maisie Knew, and portrayed Paul Raymond in the biopic The Look of Love. He co-wrote, produced and starred in the film adaptation Philomena, alongside Judi Dench, which earned him a Golden Globe and BAFTA nomination, and two Academy Award nominations, for Best Adapted Screenplay and Best Picture. He has been cast in the lead role for the ABC television pilot Doubt created by David Shore.