The Sixth Avenue Line platforms opened in 1940, completing construction of the first phase of the Independent Subway System (IND).

[4] The New York Public Service Commission adopted plans for what was known as the Broadway–Lexington Avenue route (later the Broadway Line) on December 31, 1907.

[12] The Broadway Line opened between 14th Street–Union Square and Canal Street in 1917; it originally only served local trains.

[20] In 1924, the IND submitted its list of proposed subway routes to the New York City Board of Transportation (NYCBOT), which approved the program.

[20] The IND started advertising bids for the section of the Sixth Avenue Line between 43rd and 53rd Streets in April 1931.

[24] In April 1935, engineers started planning in earnest for the Midtown portion of the Sixth Avenue Line.

[25] The city government issued corporate stock to pay for the $53 million cost of the project, since the line was not eligible for federal Public Works Administration funds.

[28][29] Mayor Fiorello H. La Guardia broke ground for the Sixth Avenue subway at Bryant Park on March 23, 1936.

[34][37] Workers had to use small charges of dynamite to avoid damaging nearby buildings or the parallel Catskill Aqueduct.

[46][47][48] On April 19, 1961, ground was broken for a $22 million project to build two express tracks between the West Fourth Street and 34th Street–Herald Square stations.

[49] The express tracks were part of an $80 million subway improvement program that began with the reconstruction of the DeKalb Avenue station in Brooklyn.

On February 9, 1983, the Metropolitan Transportation Authority (MTA) announced that it had awarded a $6.1 million contract to replace 16 escalators at the station to two companies.

[56] In the early 1990s, the station received another major repair, which included an upgrade for ADA-accessibility and modernized wall tiling.

[57] William Nicholas Bodouva & Associates, the renovation architects, also intended to streamline various passageways and ramps that had been added piecemeal over the years.

[57] On August 28, 2004, Shahawar Matin Siraj and James Elshafay were arrested for planning to bomb the Herald Square station during the 2004 Republican National Convention.

Elshafay cooperated with prosecutors and received a plea deal; Siraj was convicted of conspiracy on four counts, the most serious of which was plotting to bomb a public transportation system, in 2006[59] and was sentenced to 30 years in prison in 2007.

[64][65] In November 2024, the United States Department of Transportation provided a $72 million grant to cover two-thirds of the design and engineering phase of the renovation of New York Penn Station.

[69][70] The tiles were manufactured at Pewabic Pottery in Michigan[71] and installed along a 165-foot-long (50 m) stretch of passageway;[70] according to Oka Doner, they were meant "to fill the underground with light and feeling".

[69] The second artwork is Halo by Nicholas Pearson and consists of seven orbs,[69] each made of coiled aluminum rods and placed on small beams above the mezzanine.

[68][72] The MTA selected these artworks, along with David Provan's Yab-Yum sculpture above the IND platform, as part of the Herald Square Subway Complex Art Competition in 1988.

[69] Herbert Muschamp of The New York Times wrote of the artworks: "Unfortunately, though one feels like a subway vandal to say so, the plan's parts don't add up to an effective whole.

The entrance on the east side of 34th Street is staffed part-time and when the token booth is closed, only two HEET turnstiles provide access to the mezzanine.

[17] As of 2023, there is a separate mezzanine at the south end of the Sixth Avenue level that has two staircases leading to each platform.

This passageway was closed in 1986 after an epidemic of sexual assaults,[77] and passengers now must walk at street level to connect to the commuter railroads and Amtrak.

[81] Proposed by the Board of Transportation in 1936,[82] the passageway was outside of fare control but was intended to relieve passenger flow at the 42nd and 34th Street stations.

On March 20, 1991, a woman was raped behind a pile of debris in the subway passageway during rush hour, which had entrances at 38th Street.

In response, on March 28, 1991, the NYCTA ordered the closing of the 15 most dangerous passageways in the system within a week, which the Transit Police and citizen advocacy groups had called for since the previous year.

Bureaucratic delays had prevented their closure, with their presentation to the MTA Board not scheduled until April 1991, after a public hearing on systemwide service reduction was to be held.

North of this station are numerous crossovers and switches that allow trains from uptown to terminate here on the express tracks during construction and closures.

[106][68] It consists of fourteen paddles,[69][106] each measuring 12 feet (3.7 m), which are painted red to match the colors of the columns on the platform.