The park is said to have originally been swampy burial ground for lepers from the nearby hospital at St James's. It was first enclosed in 16th century when it formed part of the estate of Poulteney family. In 1668 an area of the Poulteney estate known as Sandpit Field was surrendered to Charles II, who made the bulk of the land into a Royal Park as "Upper St James's Park" and enclosed it with a brick wall. He laid out the park's main walks and built an icehouse there to supply him with ice for cooling drinks in summer. The Queen's Walk was laid out for George II's queen Caroline; it led to the reservoir that held drinking water for St James's Palace, called the Queen's Basin. At the time, the park was on the outskirts of London and remained an isolated area well into the 18th century, when it was known as a haunt of highwaymen and thieves; Horace Walpole was one of many to be robbed there. It was a popular place for ballooning attempts and public firework displays during the 18th and 19th centuries. The station was opened on 15 December 1906 by the Great Northern, Piccadilly and Brompton Railway (GNP&BR), the precursor of the Piccadilly line. When the station was rebuilt in 1933 with escalator access to the platforms, a new sub-surface ticket hall was built to the west under the roadway and new station entrances were constructed on the corner of Piccadilly and Stratton Street and on the south side of Piccadilly. With the rebuilding of the station and similar works at Hyde Park Corner, the little-used Piccadilly line station between the two at Down Street was taken out of use.
The Victoria line platforms opened on 7 March 1969; interchange between that line and the Piccadilly line was via the ticket hall (without having to pass through the exit barriers). Even today changing between the Jubilee and Victoria lines and the Piccadilly line involves a long walk. In 2008 TfL proposed a project to provide step-free access to all three lines. Work commenced in May 2009 to install two lifts from the ticket hall to the Victoria line platforms and an existing interchange passageway giving access to the Piccadilly and Jubilee lines platforms from the lower lift lobby. This work was completed ahead of schedule in August 2011 when the new lifts were brought into service, along with a third lift between street level on the south side of Piccadilly and the ticket hall. All platforms have level access to the trains, making the station fully accessible (the first one within the Circle line). The station has lifts, escalators, payphones, wi-fi, cash machines and Euro cash machines.