He became involved in amateur theatre through the Barnes Theatre Club. After some backstage experience there, he took on acting roles. He caught the attention of an acting agent in a production of Tess of the D'Urbervilles, and began looking for professional roles.

Since then he has performed in an amateur version of Macbeth at the Old Sorting Office Arts Centre (also in West London), as well as trying his hand at modelling, for which he was sometimes credited as Robert Thomas-Pattinson.

He had supporting roles in the made for television film Ring of the Nibelungs (2004), and in director Mira Nair’s 2004 Vanity Fair, although his scenes in the latter were deleted, and only appear on the DVD version.

He was slated to appear in a stage production of The Woman Before in May 2005, but was fired shortly before the opening night. He was replaced by Tom Riley.

In late 2005, Pattinson appeared as the character Cedric Diggory in the film Harry Potter and the Goblet of Fire. Consequently, he was named that year's British Star of Tomorrow by Times Online and has more than once been touted as the next Jude Law, and was considered for the 2007 membership list for The Coterie as an honorary member.. He names Jack Nicholson as his acting inspiration.

He has a role in the as-yet unreleased short film The Summer House, the film How To Be and will next work on the vampire film After Dark.