Boylston and Park Street were the first two stations built in the Tremont Street subway.
The subway was constructed between 1895 and 1897, and first broke ground on the site of the current Boylston station.
When the station opened in 1897, it became the first underground rapid transit station in the United States.
 
Boylston and Park Street were built with rectangular stone headhouses designed by Edmund M. Wheelwright that did not aesthetically match the Common.
Unlike the interior decor, the headhouses were sharply criticized as "resembling mausoleums" and "pretentiously monumental".
Later stations on the East Boston Tunnel and Washington Street Tunnel incorporated this criticism into their more modest headhouses.

As opened, the inner tracks at Boylston ran between the Public Garden incline to the west and the inner loop at Park Street, while the outer tracks ran between the Pleasant Street incline to the south and the outer through tracks at Park Street.
Most streetcars from the west looped at Park Street, while those from the south continued through to North Station.
From 1901 to 1908, Main Line Elevated trains ran on the outer tracks (with temporary high-level wood platforms) while streetcars continued to use the inner tracks.

The Boylston Street incline (replacing the Public Garden incline) and Boylston Street subway opened on October 3, 1914, both using the inner tracks.
On October 10, the fence dividing the northbound platform was opened, allowing passengers from the west to transfer to northbound streetcars from the south.
On October 9, 1915, the fence was again closed, forcing passengers from the west to transfer at Park Street (after cars from the south had dropped off many passengers) rather than at Boylston Street.

The 1947 state act that created the Metropolitan Transit Authority (MTA) from the Boston Elevated Railway established four immediate projects for the new agency, one of which was expansion of the Tremont Street Subway to four tracks between Park Street and Scollay Square.
As part of the plan, Park Street and Boylston stations were to be combined into a single Boston Common station, with a direct entrance from an underground parking garage.
The garage ultimately opened in 1961, but the stations were not combined.

The exit-only north headhouse on the southbound platform was removed in 1958, followed by its northbound twin around 1962.
On November 19, 1961, the Lenox Street line was substituted with buses.
A shuttle service was run between Boylston and Pleasant Street until April 6, 1962, at which time the outer tracks at Boylston were closed.
In 1964, the Tremont Street subway, including Boylston station, was designated a National Historic Landmark.
Of the two original stations, Boylston retained more of its original appearance, having undergone only minimal changes in over a century of continuous operation.
The sub-passage between the platforms was closed around 1968, and permanently sealed off in 1981.
In 1974, local students installed nine colorful panels in the station as part of the MBTA's arts program.

The northbound outer track was removed in 1983.
A planned renovation in 1986 was deferred by the station's historic status, though the disused outer tracks were fenced off.
The MBTA again planned a renovation of the station – including elevators for accessibility – in 1990, but not did construct the project.
In mid-2006, the MBTA installed brighter lighting at Boylston station, as well as modern electronic faregates and fare vending machines for the CharlieCard system.

Plans for the South Boston Piers Transitway (later part of the Silver Line) were approved in 1993, calling for a bus rapid transit level at Boylston under the Green Line level.
This portion was deferred in 1999, to become Phase III of the project.
Silver Line service on the surface, running on Tremont Street, began stopping at Boylston in December 2001.
After substantial increases in projected cost, Phase III was cancelled in 2010.

In 2019, the MBTA indicated that Boylston was a "Tier II" accessibility priority pending the result
Boylston and Park Street were the first two stations built in the Tremont Street subway. The subway was constructed between 1895 and 1897, and first broke ground on the site of the current Boylston station. When the station opened in 1897, it became the first underground rapid transit station in the United States.  
Boylston and Park Street were built with rectangular stone headhouses designed by Edmund M. Wheelwright that did not aesthetically match the Common. Unlike the interior decor, the headhouses were sharply criticized as "resembling mausoleums" and "pretentiously monumental". Later stations on the East Boston Tunnel and Washington Street Tunnel incorporated this criticism into their more modest headhouses.
As opened, the inner tracks at Boylston ran between the Public Garden incline to the west and the inner loop at Park Street, while the outer tracks ran between the Pleasant Street incline to the south and the outer through tracks at Park Street. Most streetcars from the west looped at Park Street, while those from the south continued through to North Station. From 1901 to 1908, Main Line Elevated trains ran on the outer tracks (with temporary high-level wood platforms) while streetcars continued to use the inner tracks. 
The Boylston Street incline (replacing the Public Garden incline) and Boylston Street subway opened on October 3, 1914, both using the inner tracks. On October 10, the fence dividing the northbound platform was opened, allowing passengers from the west to transfer to northbound streetcars from the south. On October 9, 1915, the fence was again closed, forcing passengers from the west to transfer at Park Street (after cars from the south had dropped off many passengers) rather than at Boylston Street. 
The 1947 state act that created the Metropolitan Transit Authority (MTA) from the Boston Elevated Railway established four immediate projects for the new agency, one of which was expansion of the Tremont Street Subway to four tracks between Park Street and Scollay Square. As part of the plan, Park Street and Boylston stations were to be combined into a single Boston Common station, with a direct entrance from an underground parking garage. The garage ultimately opened in 1961, but the stations were not combined.
The exit-only north headhouse on the southbound platform was removed in 1958, followed by its northbound twin around 1962. On November 19, 1961, the Lenox Street line was substituted with buses. A shuttle service was run between Boylston and Pleasant Street until April 6, 1962, at which time the outer tracks at Boylston were closed. In 1964, the Tremont Street subway, including Boylston station, was designated a National Historic Landmark. Of the two original stations, Boylston retained more of its original appearance, having undergone only minimal changes in over a century of continuous operation. The sub-passage between the platforms was closed around 1968, and permanently sealed off in 1981. In 1974, local students installed nine colorful panels in the station as part of the MBTA's arts program.
The northbound outer track was removed in 1983. A planned renovation in 1986 was deferred by the station's historic status, though the disused outer tracks were fenced off. The MBTA again planned a renovation of the station – including elevators for accessibility – in 1990, but not did construct the project. In mid-2006, the MBTA installed brighter lighting at Boylston station, as well as modern electronic faregates and fare vending machines for the CharlieCard system.
Plans for the South Boston Piers Transitway (later part of the Silver Line) were approved in 1993, calling for a bus rapid transit level at Boylston under the Green Line level. This portion was deferred in 1999, to become Phase III of the project. Silver Line service on the surface, running on Tremont Street, began stopping at Boylston in December 2001. After substantial increases in projected cost, Phase III was cancelled in 2010.
In 2019, the MBTA indicated that Boylston was a "Tier II" accessibility priority pending the result
Boylston station