Fans gather on the site annually on the anniversary of Bill Mazeroski's World Series winning home run, in what author Jim O'Brien writes is "one of the most unique expressions of a love of the game to be found in a major league city".

[13] In 1903, Pittsburgh Pirates' owner Barney Dreyfuss began to look for ground to build a larger capacity replacement for the team's then-current home, Exposition Park.

"[16] The site was initially labeled "Dreyfuss's Folly" due to its long distance—a 10-minute trolley ride—from downtown Pittsburgh, but the land around the park developed and criticisms were dropped.

[17][18] Dreyfuss announced that unlike established wooden ballparks such as the Polo Grounds, he would build a three-tiered stadium out of steel and concrete to increase longevity—the first of its kind in the nation.

[15][23] Though the scoreboard was operated by hand,[24] the ballpark featured multiple innovations such as ramps and elevators to assist fan movement throughout the park, a room for the umpires, and a visiting team clubhouse similar to the Pirates'.

The first game was played at Forbes Field on June 30, 1909, one day after the Pittsburgh Pirates had defeated the Chicago Cubs, 8–1, at Exposition Park.

[22] Pittsburgh Mayor William A. Magee threw out the stadium's ceremonial first pitch,[27] tossing it from the second tier to John M. Morin, Director of Public Safety, on the field below.

[29] The Pittsburgh Press wrote, "the ceremonies were witnessed by the largest throng that ever attended an event of this kind in this or any other city in the country...Forbes Field is so immense—so far beyond anything else in America in the way of a baseball park—that old experts, accustomed to judging crowds at a glance, were at a loss for reasonable figures.

15][Pittsburgh Daily Post, February 13, 1921, p. 18] In 1925, seating capacity received a bigger bump when the right field grandstand was extended into the corner and into fair territory, replacing a section of wooden bleachers.

[Pittsburgh Sun-Telegraph, April 21, 1946, p. 21] Although Forbes Field developed a reputation as a "pitcher-friendly" ballpark, there was never a no-hitter thrown in the more than 4,700 games at the stadium.

[38] At some point prior to July 26, 1943, evidently prompted by numerous instances of the relocated cage continuing to impact balls in play,[38][39][40] the Pirates finally settled on what would become its permanent and, by far, best-remembered home: in fair territory, just to the left of the 457-foot (139 m) marker in deepest left-center.

Some sources also stated 408 feet (124 m) as a right-center distance, to the unmarked point where the center field wall intersected the end of the double-deck stands.

[22] Ticket prices were considered high for the day and steel pillars supporting the roof occasionally blocked fans' views of the field.

[42] When winning streaks attracted high attendance to games, fans were permitted to sit on the grass in right field, provided they agreed to allow a player to catch any ball hit in the area.

[52] Following a plan to expand their adjacent campus, the University of Pittsburgh purchased Forbes Field in 1958, with an agreement to lease the stadium to the Pirates until a replacement could be built.

[55] The 40,918 spectators in attendance stood and cheered as Dave Giusti retired Willie Smith for the final out (recorded by Bill Mazeroski) at the stadium.

A community group attempted to rescue the structure from demolition, proposing such things as a stage, apartments and a farmers market for the site and comparing it to the Eiffel Tower in significance.

[28] The portion of the left field wall over which Bill Mazeroski hit his walk-off home run to end the 1960 World Series, between the scoreboard and the "406 FT" sign, no longer stands at its original location.

[64][67] However, its location has been altered; author John McCollister wrote, "Had architects placed home plate in its precise spot about half of the Pirates fans could not view it.

"[68] However, the original location of the home plate has been more recently determined by others to be approximately 81 feet (25 m) away from its current display, just inside the GSPIA/Economics Library, and not in a restroom as has been popularly believed.

[63][70][71] The tradition was started by Squirrel Hill resident Saul Finkelstein, who at 1:05 pm on October 13, 1985, sat alone at the base of the flagpole and listened to the NBC radio broadcast of Chuck Thompson and Jack Quinlan.

[31] Harold Arlin announced the play-by-play action between the Pittsburgh Pirates and the Philadelphia Phillies over KDKA from a box seat next to the first-base dugout.

[75] Regular broadcasts of Pirates games began over KDKA in 1936, announced by A. K. "Rosey" Rowswell, a local humorist and friend of team owner Bill Benswanger.

[31] On May 28, 1956, Dale Long of the Pirates took what one author has stated was the first-ever curtain call in baseball history, after hitting home runs in eight consecutive games caused fans to cheer for five minutes.

[89][92] During their years at Forbes Field, Pitt's teams were led by Hall of Fame coaches Joe Thompson, Glenn "Pop" Warner and Jock Sutherland.

The 1926 Carnegie Tech Tartans football team pulled off one of the greatest upsets in sports history by defeating the 8–0 Notre Dame Fighting Irish, shutting them out, 19–0.

[101] The University of Pittsburgh's acquisition of Forbes Field in 1958 gave the Steelers some options, and they began transferring some of their home games to the much larger Pitt Stadium that year.

[104] Two years later, on June 18, 1941, Conn fought Joe Louis at New York City's Polo Grounds, in an attempt to become the world heavyweight champion.

The Pirates and the New York Giants, who were playing at Forbes Field, were called into their dugouts while the 24,738 fans in attendance listened to the radio broadcast of the hour-long bout.

[105] On Sunday, October 17, 1909, at 3:00 p.m. a communion service was held at Forbes Field as the culmination of the International Centennial Celebration and Conventions of the Disciples of Christ[106] marking the 100th anniversary of the signing of the "Declaration and Address" by Thomas Campbell in September 1809.