Ira Samuel Einhorn was born on May 15, 1940, in Philadelphia, Pennsylvania. He grew up in a middle-class Jewish family. As a child, he attended local schools and later went to Central High School, a well-known public school in Philadelphia.

After high school, Ira went on to study at the University of Pennsylvania. He earned his bachelor's degree in English in 1961 and returned to complete some graduate studies in English in 1963. While at university, he became involved in several social and political movements. He took part in ecological groups and was active in the counterculture, anti-establishment, and anti-war movements that emerged in the 1960s and 1970s.

Einhorn became known for his environmental activism. He spoke at the first Earth Day event in Philadelphia in 1970. However, there are some claims that he exaggerated his role in founding the event. As part of his career, he also worked as an English instructor at Temple University during the 1964–1965 academic year. His contract was not renewed after he expressed a dislike for the academic world and made comments about drug use in an interview.

Ira Einhorn had a five-year relationship with Holly Maddux, a college graduate from Texas. In 1977, after their breakup, Maddux returned to their shared apartment in Philadelphia on September 9 to collect her things. She was seen that day but never again. Einhorn told police that she left to buy food and did not return.

Several weeks later, police became suspicious of Einhorn after neighbors complained about a terrible smell coming from his apartment. Eighteen months later, on March 28, 1979, the police found Maddux's decomposed body in a trunk inside Einhorn's closet. After police discovered the remains, Einhorn said, "You found what you found."

Einhorn's lawyer managed to get him released on bail of $40,000. Einhorn later fled the U.S. just before his trial was supposed to start in 1981. He spent the next seventeen years in Europe, living under a fake name and marrying a woman from Sweden. Meanwhile, authorities in Pennsylvania convicted him in absentia of Maddux's murder in 1996 and sentenced him to life in prison.

In 1997, Einhorn was arrested in France while living under another identity. He fought against extradition for several years, using various legal tactics. In 2001, after a complex legal process, he was extradited back to the United States.

During his trial in 2002, Einhorn claimed that CIA agents killed Maddux and framed him. However, the jury convicted him after only two hours of deliberation. He received a life sentence without the possibility of parole at Pennsylvania State Correctional Institution Houtzdale.

Einhorn's conviction was upheld in 2006. He died in prison on April 3, 2020, reportedly from natural causes.