Ruby Jackson was born on August 31, 1909, in Zuber, Florida. She was the second child and first daughter of Gertrude and William Jackson. Ruby grew up in a family with six siblings. They all attended local segregated schools, which were common for Black children in the South during that time. Recognizing Ruby's intelligence, her parents sent her to a private school for Black children called Fessenden Academy. There, she trained to become a teacher.

In 1931, Ruby married Sam McCollum. Following their marriage, the couple moved to Nyack, New York. This move was part of the Great Migration, a movement of many rural Black families escaping difficult conditions in the South and seeking better opportunities in northern cities. Ruby and Sam had three children together: Sam Jr., Sonja, and Kay. Ruby later stated that her youngest child, Loretta, who was born in Live Oak, was fathered by a white doctor named C. Leroy Adams during a forced relationship.

In 1934, Ruby and Sam moved to Fort Myers, Florida. Sam’s brother, Buck McCollum, had become wealthy from running a Bolita gambling business. Sam became involved in this business and was reported to be active in various illegal activities, including gambling and liquor sales. Despite the illegality of these operations, they thrived because of payoffs to local law enforcement. Along with gambling, the McCollums sold burial policies and owned a funeral home.

During the late 1940s and early 1950s, the McCollums were well-known and somewhat prosperous in their community. They owned a large two-story home in Live Oak, a small town in Florida, and Ruby drove a new Chrysler each year. The family also owned several juke joints where they served illegal liquor. They managed a farm outside of town that had the largest tobacco allotment in Florida. Ruby was considered one of the wealthiest Black women in northern Florida.

The McCollums were active in their church and well-respected in their community. By 1952, their oldest son, Sam Jr., had started college at UCLA.

On August 3, 1952, Ruby McCollum visited the office of Dr. C. Leroy Adams in Live Oak, Florida. She arrived with her two young children. Ruby later admitted to shooting Adams four times with a revolver. She said she did this because he would not agree to leave her alone. Ruby claimed that over the years, Adams had forced her into sexual relations and had fathered her child, a two-year-old daughter named Loretta.

After the shooting, Ruby was arrested and taken to a state prison for her protection. The following day, her husband Sam suffered a heart attack and died while the couple's children were with Ruby's mother. People in the community believed Sam had known his life was over after Ruby shot Adams.

Ruby's trial began with attorney Frank Cannon defending her against state's attorney Keith Black. The trial was presided over by Judge Hal W. Adams, who was not related to the victim. The jury was made up entirely of white men, some of whom had been patients of Dr. Adams. Ruby testified that Adams had raped her multiple times and had insisted she bear his child. However, many of her statements were not allowed in court due to objections from the prosecutor.

Despite Ruby's claims of self-defense, the prosecution argued that she shot Adams in anger over a billing dispute. The jury ultimately convicted Ruby of first-degree murder on December 20, 1952, and she was sentenced to death by electric chair.

Ruby's case was appealed, and on July 20, 1954, the Florida Supreme Court overturned her conviction on a technicality. Due to concerns about her mental health, her attorney entered a plea of insanity during her second trial. She was found mentally incompetent and committed to the Florida State Hospital for mental patients in Chattahoochee, Florida.

Ruby remained there until 1974 when her attorney successfully sought her release under the Baker Act. After her release, she lived in a rest home in Silver Springs, Florida, funded by a trust from William Bradford Huie, an author who wrote about her case. Ruby was able to reunite with her children, but her family had its struggles.

Ruby McCollum passed away on May 23, 1992, at the age of 82, due to a stroke. She was buried next to her brother in a cemetery in Live Oak, Florida.