The Great Northern railway (GNR) and its successor, the London and North Eastern Railway (LNER), for many years refused consent for any extension into the suburbs of Haringey and Enfield. Eventually, public opinion became strong enough to force the matter and in the 1930s the line was rapidly extended from Finsbury Park to Cockfosters via Arnos Grove. The station was opened on 19 September 1932 as the most northerly station on the first section of the Piccadilly line extension. It was the terminus of the line until services were further extended to Oakwood on 13 March 1933. Its name was chosen after public deliberation: alternatives were "Arnos Park", "Bowes Road" and "Southgate". On the night of 13 October 1940, during the Blitz, a lone German aircraft dropped a single bomb on houses to the north of Bounds Green station. The destruction of the houses caused the north end of the westbound platform tunnel to collapse. As a result, train services between Wood Green and Cockfosters were disrupted for two months.
Like the other stations Charles Holden designed for the extension, Arnos Grove was built in a modern European style using brick, glass and reinforced concrete and basic geometric shapes. A circular drum-like ticket hall of brick and glass panels rises from a low single-storey structure and is capped by a flat concrete slab roof. The design was inspired by the Stockholm City Library and Swedish architect Gunnar Asplund. The centre of the ticket hall is occupied by a disused ticket office (a passimeter in London Underground parlance) which houses an exhibition on the station and the line.
Three parallel train tracks pass through the station, with two double-sided platforms between the central track and the outer tracks. The edges of the platforms are labelled platform 1 and 2, and platform 3 and 4, in such a way that the two outer tracks are accessible from platforms 1 and 4, and the central track, usually used by trains that terminate and reverse at Arnos Grove station, is accessible from platforms 2 and 3. Platforms 1 and 2 are designated for trains to Cockfosters while platforms 3 and 4 are for trains to Central London. In 2005 the station underwent a refurbishment programme including improvements to signage, security and train information systems. General repairs and redecoration were carried out, flooring was renewed, and better lighting, an improved CCTV security system and Help Points were installed, with the latter being suitable for people with limited hearing. The station has payphones, a waiting room and a bridge.
Connections: London Bus routes 34, 184, 232, 251, 298 and 382 and night route N91 serve the station.