Gerhard Arthur Puff was born on February 13, 1914, in Dresden, Germany. He grew up in a time when Germany was changing rapidly. When he was 13 years old, he moved to the United States with his family. On June 6, 1927, Puff, along with his mother and five-year-old brother, arrived at Ellis Island after traveling on a ship called the SS Columbus from Bremen.

After arriving in the U.S., Puff and his family settled in Milwaukee, Wisconsin. They started a new life there. In 1934, Puff became a naturalized citizen. This meant he was officially recognized as a citizen of the United States. However, by 1940, Gerhard Puff found himself in trouble with the law. He was an inmate in the Wisconsin State Prison located in Waupun, Wisconsin.

Over the next decade, Puff continued to get into trouble. He spent time in and out of prison for various offenses. His crimes included disorderly conduct, theft of domestic animals, assault, and more serious charges like intent to commit armed robbery. He also faced charges for escaping custody, driving stolen vehicles, breaking and entering, and escaping from prison.

Puff's legal troubles escalated in 1951 when he was arrested by the Milwaukee Police for armed robbery. He was held on a $3,000 bond while awaiting trial. During his time in jail, Puff met another man known as George Arthur Heroux, who was on the FBI's Ten Most Wanted list. A few months after his arrest, Puff's bond was paid by an unknown person, but he did not return to court as scheduled.

In November of 1951, Gerhard Arthur Puff and George Arthur Heroux committed a bank robbery at the Johnson County National Bank and Trust Company in Prairie Village, Kansas. They stole more than $62,000 in cash, a large number of travelers' checks, and unissued government bonds. The robbery involved threatening the bank tellers at gunpoint to open the vault. After the heist, they escaped in a stolen convertible.

Both Puff and Heroux were placed on the FBI Ten Most Wanted Fugitives List. Heroux was arrested in Miami, Florida, on July 25, 1952. The FBI tracked Puff to Manhattan, where he stayed at the Congress Hotel. On July 31, 1952, agents waited to arrest him. Puff left his hotel room but encountered FBI Special Agent Joseph John Brock in the lobby. In a confrontation, Puff shot Brock twice in the chest and took his gun. Then, Puff began firing another shot at the agents surrounding him.

Puff continued to evade capture for a brief time until he was shot by FBI agents and collapsed in the street. He was rushed to a hospital for treatment but was later moved to the prison ward at Bellevue Hospital. Agent Brock, however, did not survive and was pronounced dead shortly after arriving at the hospital.

On May 15, 1953, Puff was found guilty of first-degree murder in a federal court. He was sentenced to death. Puff's attorney appealed the conviction, but the appeal was denied. He was executed on August 12, 1954, using the electric chair at Sing Sing Prison in Ossining, New York. Puff was declared dead at 11:08 PM, becoming one of the first individuals executed by the state using this method.