Miller's journey into the limelight began on the stages of London's theater scene. Her early years were marked by a passion for the dramatic arts, and she honed her craft in various productions. However, it was her foray into film that catapulted her into the global spotlight.
In the early 2000s, Sienna Miller garnered attention for her breakout roles in films that showcased her natural acting ability. "Layer Cake" (2004) served as a stepping stone, but it was her portrayal of Nikki in "Alfie" (2004) that garnered widespread recognition. The film, a remake of the 1966 classic, showcased Miller alongside Jude Law, marking the beginning of a high-profile period in her career.