Joseph Daniel Miller was born on September 2, 1964, in Steelton, Pennsylvania. He grew up in a poor family with three brothers and a sister. From a young age, Joseph showed signs of having an intellectual disability. He had difficulty learning and suffered from a condition called anterograde amnesia, which made him forget new information. Because of these challenges, he was often bullied by his classmates. Eventually, he dropped out of school after completing only the fourth grade.

Joseph's home life was troubled. Both of his parents were abusive, both physically and emotionally. This abuse had a lasting impact on his mental health. During his childhood, he faced additional harm when he was sexually harassed by an uncle. Under the influence of his older brother, he started engaging in petty theft and drinking alcohol.

In 1970, a serious incident involving Joseph's family occurred. His older sister, just 15 years old at the time, gave birth to a daughter. She reported to the police that her father had sexually abused her for two years. This accusation led to investigations, but Joseph's father was never charged due to a lack of evidence and threats made against the sister.

As a child, Joseph faced further violence. At the age of 12, he was beaten up by a group of peers in a street fight. In response, he took a shotgun from his father, found the boys responsible, and shot at them, injuring several. He was caught quickly and sent to a juvenile detention center. While there, he faced sexual assault by other inmates and abuse from the staff. This traumatic experience contributed to symptoms similar to post-traumatic stress disorder (PTSD).

Joseph was released from the detention center in the early 1980s. However, he soon fell back into a life of crime and drug use. He was arrested several times for offenses such as theft, assault, arson, and illegal possession of firearms. At one point, he even suffered a near-fatal drug overdose.

In 1984, Joseph left Steelton and moved to Harrisburg, Pennsylvania. During this time, he found a place to live and got married. He and his wife had three children between 1985 and 1993. Due to his lack of education, he worked at low-skilled jobs but frequently changed his employment.

On August 5, 1992, Joseph Daniel Miller went to a bar in Harrisburg with a friend. There he met Clara Johnson, a black girl, and offered her a ride home. Clara agreed but only if Miller's friend joined them. After they all got in the car, Miller dropped off his friend against Clara's wishes. He then drove to a vacant lot near some train tracks. There, a violent confrontation happened. Miller beat Clara, tied her up, and raped her twice. After the second assault, he tortured her and dragged her to a ditch, where he intended to kill her. At that moment, police arrived after receiving a report of trespassing. Miller escaped, leaving Clara and his car behind. Police quickly found Clara and discovered incriminating evidence in Miller's vehicle. Miller was soon placed on a wanted list as a fugitive.

The next day, police found Miller hiding in Steelton, at a relative's house. He fought against the arresting officers, even barricading himself on the roof and threatening suicide. After a six-hour negotiation, he surrendered. While in custody, Miller waived his rights and confessed to murdering two girls. He described an incident on May 15, 1987, when he attacked 18-year-old Selina Franklin after most of her friends left his car. He raped and strangled her. He also confessed to killing 23-year-old Stephanie McDuffey on November 6, 1989, after offering her a ride home and then assaulting her in a similar manner. Miller provided police with the locations of the burial sites, leading to the discovery of their bodies in August 1992.

Shortly after, he admitted to the murder of 25-year-old Jeanette Thomas, whose body was found shortly after she went missing in January 1990. During the investigation of Jeanette's case, another man, William Kelly Jr., had confessed and been convicted. However, his confession was later deemed questionable due to his mental health issues. In 1993, Miller was convicted of the murders of Selina and Stephanie, as well as the kidnapping and rape of Clara Johnson, receiving a death sentence. Over time, he filed appeals, but they were all denied.

In the late 1990s, Miller confessed to murdering Kathy Schenk, who he had picked up in February 1990 and subsequently raped and strangled. He was convicted and received a life sentence. In 2014, DNA analysis led to the identification of another victim, Kelly Ann Ward, who had been missing since 1986. Because of the similarities to his known victims, Miller became a suspect. In April 2016, he confessed on tape to the murders of both Kelly and Jeanette, expressing a desire to plead guilty and apologizing to their families.

In June 2016, Miller returned to Harrisburg for a trial related to these confessions and was found guilty of those murders, resulting in two more life sentences. He remains incarcerated at the State Correctional Institution - Camp Hill.