Weeks's debut film as a child actor was The Little Vampire (2000), directed by Ulrich Edel, which earned Weeks a Young Artist Award nomination. He also appeared in Stephen Poliakoff's The Lost Prince (filmed 2002, released 2003) as the young George, Duke of Kent, in a film about the disabled Prince John. This was followed by roles in Girl With a Pearl Earring (2003) and The Queen of Sheba's Pearls (2004). His second turn as a title character came as Scipio in The Thief Lord (2006), a movie based on Cornelia Funke's novel The Thief Lord and directed by Richard Claus. Weeks has also appeared in two television shows: Berkeley Square (1998) as Lord Louis Wilton and Goggle Eyes (1993) as Joseph. In 2009 he appeared in the second part of the Shark Week special Blood in the Water and played the character Guido in Chéri. In 2010, he played Jacob in Booked Out, about the lives of characters within an aging block of flats.