Willie Luther "Bill" Steelman was born on March 21, 1945, in San Joaquin County, California. He was the youngest of three children in the Steelman family. His parents, Lester Steelman and Ethel (née Hogan), had moved to California from Oklahoma in 1935. Lester worked as a foreman on a farm in San Joaquin. The family did not have much money but were very close to each other. With both parents working, Steelman's care largely fell to his 14-year-old sister, Frances.

Steelman grew up in Lodi, California, where he attended Lodi High School. During his time in school, he was not popular and was often seen as a social outcast, though he did not suffer from bullying. When he was just 13 years old, his father passed away. This event had a heavy impact on him, and not long after, he dropped out of school and started to engage in petty crimes. He resisted his mother's attempts to encourage him to return to his studies or find a job. He would often threaten her if she tried to persuade him otherwise. A year later, his mother remarried. Even though they stayed close, she frequently expressed disappointment in Steelman's lifestyle choices, especially when compared to his brother, Gary.

In March 1962, Steelman's mother and stepfather convinced him to enlist in the United States Navy. However, his service ended after just a few months. In the fall of 1962, he moved to Denver to live with his sister, but she soon had to evict him due to his unruly and threatening behavior. Steelman returned to California to stay with his mother.

By January 1965, Steelman faced legal troubles, being convicted of forgery. He was placed under the custody of the California Youth Authority and sent to Pine Grove Work Camp, where he stayed for seven months. After his release, he started working as a field hand but soon got into trouble again. He married a 15-year-old girl shortly after meeting her, but he quickly quit his job and they moved into his mother's home. In December 1965, a warrant was issued for his arrest after he cashed stolen checks. He was apprehended in January and later attempted suicide while in jail.

In February 1966, Steelman was transferred to Stockton State Hospital after being classified as mentally ill. He later moved to Atascadero State Hospital and showed improvement. He was sentenced to 14 months in prison for a forgery conviction, serving at the California Men's Colony where he was a model inmate. After just two months, he was paroled and went back to Lodi, claiming he had turned his life around.

However, Steelman was soon arrested again for supplying drugs to minors. After spending a short time in jail, he moved in with a woman named Kathy Stone and later married Denise Machell in June 1969. They lived in various places, including Sacramento and Mountain View. Throughout the early 1970s, Steelman continued to get into trouble with the law for different offenses, and by 1972 he had developed a dependency on drugs. His wife eventually left him on New Year's Day in 1973, citing his refusal to change and the difficulties they faced as a couple.

In October 1973, Willie Steelman and Douglas Gretzler began a violent crime spree across several states. The pair started by abducting Kenneth Unrein and Michael Adshade at gunpoint in Colorado. They forced the two men to drive them to California, where they subsequently killed them by strangling and stabbing. Their bodies were hidden in a creek.

Just a few days later, they attempted to rob a couple, James Fulkerson and Eileen Hallock. They were taken hostage but later released. Steelman and Gretzler continued their rampage by picking up hitchhiker Steven Loughran, whom they murdered after forcing him to crawl inside a sleeping bag in a remote area near Phoenix.

Steelman then convinced Gretzler to kill Robert Robbins, a young man living with an acquaintance, Katherine Mestites. They strangled Robbins and shot Mestites shortly after, concealing their bodies.

The next major crime involved abducting Gilbert Sierra, whom they forced into the trunk of his car. They took him to a desert area and shot him dead.

Following Sierra's murder, they encountered Vincent Armstrong, who managed to escape after being ordered to drive while they threatened him with a gun.

Their last known victims were Michael and Patricia Sandberg. After taking them hostage in their home, they brutally murdered the couple, along with their two children, Robert and Lisa, and the babysitter.

Police later discovered all four bodies in the Sandbergs' residence. With several leads pointing to Steelman and Gretzler, law enforcement launched a massive manhunt, leading to their arrest on November 8, 1973. They were eventually convicted for their crimes and sentenced to death and life imprisonment.