Middlemarch can be described as a Vogel period gable station, the common appearance being derived from the simple rectangular shape and gable ends. There are rusticated weatherboards and a corrugated iron roof. In common with other gable stations, there is little decoration. There is no verandah, and the building is set very close to the track. Divided into four separate rooms - Post Office, station office, recessed lobby, and ladies' waiting room - the platform elevation has a line of double-hung sash windows and two separate entrances. There is another entrance with a porch and lean-to additions at the end of the building.
The Otago Central Railway opened as far as Middlemarch in 1891, and plans for a station building had been drawn up two years earlier. The contractor was William Sanderson and the station was completed in early 1891. The work ran slightly over cost. The arrival of the railway saw the town grow dramatically. Photographs suggest that Middlemarch began as a smaller building with an open lobby, later filled in. At some stage a Post Office was added to the south end. In 1964 the ladies' waiting room was converted into an office for the Inspector of Permanent Way, at a cost of £300. The following year the station office was partitioned and the walls lined. It became a flag station, attended by a caretaker, in 1980, the same year that the stockyards closed. Six years later the station closed to less-than-wagonload freight. The Otago Central Branch closed in 1990, but the Taieri-Middlemarch section was purchased by Dunedin City Council. Tourist trains operated by the Otago Excursion Train Trust run in summer.