On February 15, 1933, Roosevelt was giving an impromptu speech from the back of an open car in the Bayfront Park area of Miami, Florida, where Zangara was living, working the occasional odd job, and living off his savings. Zangara joined the crowd, armed with a .32-caliber pistol he had bought at a local pawn shop. However, being only five feet tall, he was unable to see over other people, and had to stand on a wobbly folding metal chair, peering over the hat of Lillian Cross to get a clear aim at his target. After the first shot, Cross and others grabbed his arm, and he fired four more shots wildly. He missed the president-elect, but five other people were hit, including Chicago mayor Anton Cermak, who was standing on the running board of the car next to Roosevelt. En route to the hospital, Cermak had allegedly told FDR, "I'm glad it was me and not you, Mr. President", words now inscribed on a plaque in Bayfront Park.
In the Dade County Courthouse jail, Zangara confessed and stated: "I have the gun in my hand. I kill kings and presidents first and next all capitalists." He pleaded guilty to four counts of attempted murder and was sentenced to 80 years in prison. As he was led out of the courtroom, Zangara told the judge: "Four times 20 is 80. Oh, judge, don't be stingy. Give me a hundred years." The judge, aware that Cermak might not survive his wounds, replied: "Maybe there will be more later."
Cermak died of peritonitis 19 days later, on March 6, 1933, two days after Roosevelt's inauguration. Zangara was promptly indicted for first-degree murder in Cermak's death. Because Zangara had intended to commit murder, it was irrelevant that his intended target was not the man he ultimately killed.
Zangara pleaded guilty to the additional murder charge, and was sentenced to die. Zangara said after hearing his sentence: "You give me electric chair. I no afraid of that chair! You one of capitalists. You is crook man too. Put me in electric chair. I no care!" Under Florida law, a convicted murderer could not share cell space with another prisoner before his execution, but another convicted murderer was already awaiting execution at Raiford. Zangara's sentence required prison officials to expand their waiting area, and the "death cell" became "Death Row".
On March 20, 1933, after spending only 10 days on Death Row, Zangara was executed in Old Sparky, the electric chair at Florida State Penitentiary in Raiford, Florida. Zangara became enraged when he learned no newsreel cameras would be filming his final moments. Zangara's final statement was "Viva Italia! Goodbye to all poor peoples everywhere! [...] Push the button!"