[6] A 19-year-old typist at the time of the incident,[7] Steinhagen had developed an obsession with Eddie Waitkus after seeing him play as first baseman with the Chicago Cubs.

[10] While she never actually met him during that time, at home she created a "shrine" to Waitkus with hundreds of photographs and newspaper clippings, often spreading them out and looking at them for hours, according to her mother.

[12] On June 14, 1949, the Phillies came to Chicago to face the Cubs; Waitkus played in the game, recording a hit and scoring two runs.

[13] After the game, which she attended, Steinhagen sent Waitkus a handwritten note through a bellboy, inviting him to visit her in her 12th floor room in the Edgewater Beach Hotel where they were both registered.

[21] While Waitkus was lying on the floor bleeding from the chest, Steinhagen called down to the front desk of the hotel and told them "I just shot a man ..."[15] Thereafter, according to a report the following day in The Miami News, she went to wait for them on the benches near the elevator;[8] however, a much later article in The Washington Times indicates she held Waitkus' head on her lap until help arrived.

[17] She told a psychiatrist before she went to court that "I didn't want to be nervous all my life",[21] and explained to reporters that "the tension had been building up within me, and I thought killing someone would relieve it"— a murderous impulse that had been with her for at least two years.

[23] At the ensuing sanity hearing (which also occurred on June 30, 1949), Dr. William Haines, a court-appointed psychiatrist, testified that Steinhagen had "schizophrenia in an immature individual" and was mentally ill.[24] Chief Judge James McDermott of the Criminal Court of Cook County then directed the jury to find her insane, and ordered her committed to Kankakee State Hospital.

[23] The bullet that struck Waitkus lodged in a lung, threatening his life and preventing his returning to baseball for the rest of the season.

[16] He returned the following year (the 1950 Phillies, nicknamed the "Whiz Kids", advanced to the World Series) and played through the 1955 season.

[12][22] Waitkus did not press charges against Steinhagen after she was released, telling an assistant state's attorney that he wanted to forget the incident.

[3] On December 29, 2012, Steinhagen died in a Chicago hospital of a subdural hematoma that was the result of an accidental fall in her home.

[3] As one of the first instances of what later became known as stalker crimes,[2][9] the incident for several years "had a profoundly anti-aphrodisiacal effect on traveling athletes", according to The Boston Globe.

[35] It prompted a magazine article from sports writer Al Stump entitled "Baseball's Biggest Headache— Dames!

[39] The incident, which required four surgeries, is said to have influenced Waitkus' career and probably his personal life as well, as his baseball statistics after the shooting were never the same,[a] and he developed a great concern that others might not understand why he had visited Steinhagen's room.