Petersham station opened in 1857.
The former Petersham railway station building is located in Terminus Street. This heritage listed building, completed in 1885, was designed by George Cowdery in the Victorian Italianate architectural style. It is the only major ‘First Class’ station building known to have been built in Sydney in the 19th century. The main block features a central tower, sandstone steps onto a veranda, supported on cast iron columns with decorative lacework. The railway platform behind it features an awning supported by cast iron columns with decorative cast iron lace work. 
The Main Suburban Railway Line through Petersham was quadruplicated in 1892, and an island platform was built to serve both ‘fast’ and ‘slow’ pairs of tracks.
The line was sextuplicated through Petersham in 1927 in association with electrification works and the island platform serving the old ‘fast’ pair of tracks (to become the ‘Up’ and ‘Down Suburban’ tracks) was demolished. An ornate station building stands to the north of the tracks, but is no longer used as part of the station. A turn-back siding previously located between the local tracks has now been removed. 
A pedestrian subway was provided in 1892 at the western end of the station, connecting Trafalgar Street with Terminus Street. Access to the platforms from this subway closed after 1988.
The footbridge remains a fascinating piece of neo-gothic architecture. Upgrades to the station took place in the late 1990s, with the wooden steps on the footbridge being replaced due to their slipperiness in wet weather, a small but high-roofed shed at the east end of the platform being removed for security reasons, and the area under the lower part of the platform stairs also being fenced-off for similar concerns.