Thomas Watt Hamilton was born on 10 May 1952 in Glasgow, Scotland. He grew up in a city known for its working-class roots and local culture. Not much is known about his family or childhood, but he eventually became involved with youth clubs in his community. Hamilton was the head of several youth clubs, where he interacted with many young boys.

In July 1973, when Hamilton was 21, he became an assistant leader with the 4th/6th Stirling troop of the Scout Association. Later that same year, he was appointed as leader of the 24th Stirlingshire troop, which was being revived. Despite his position, he faced multiple complaints about his leadership. People raised concerns about the Scouts being forced to sleep closely with him inside his van during outdoor activities.

By May 1974, just a few months after taking the leader position, his Scout Warrant was withdrawn. The County Commissioner for the Scouts expressed doubts about Hamilton's moral intentions towards the boys. Following this, he was blacklisted by the Scout Association. Attempts he made to become a Scout leader in other areas were unsuccessful.

Throughout the years, Hamilton claimed that rumors about his behavior negatively impacted his life and led to the failure of his business in 1993. In the last months of his life, he expressed feelings of being persecuted by local police and community organizations while trying to start a boys' club. He even wrote to notable figures such as Queen Elizabeth II and his local Member of Parliament about his complaints.

In the 1980s, another MP, George Robertson, voiced concerns about Hamilton's local boys' club, which his son attended. Hamilton's interactions with law enforcement were noted in various investigations, but these did not result in significant action during his lifetime.

Hamilton’s life came to an end when he died on 13 March 1996. He was cremated six days later.

On March 13, 1996, Thomas Watt Hamilton committed a mass shooting at Dunblane Primary School in Scotland. He began the day by scraping ice off his van outside his home in Stirling at around 8:15 a.m. After that, he drove about five miles to Dunblane. He arrived at the school around 9:30 a.m. and parked near a telegraph pole. Hamilton cut the telephone cables at the pole before walking across the parking lot to the school.

He approached the northwest side of the school and entered through a door near the toilets and gymnasium. Hamilton was armed with four handguns: two 9mm Browning HP pistols and two Smith & Wesson M19 .357 Magnum revolvers, and he carried 743 rounds of ammunition. Inside the gymnasium, a class of 28 Primary 1 pupils was preparing for a physical education lesson, supervised by three staff members.

Before he entered the gym, Hamilton fired two shots into the assembly hall and the girls' toilet. Once in the gym, he started shooting at people inside. He injured PE teacher Eileen Harrild as she tried to shield herself. Harrild fled to a store cupboard with several injured children. Hamilton shot and killed Gwen Mayor, the Primary 1 teacher, instantly, and injured the other adult present, Mary Blake, who also managed to make her way to the cupboard.

Within just moments, Hamilton had fired 29 shots, killing one child and injuring several others. He continued shooting as he moved through the gym, firing a total of 106 shots during the attack. He shot at children who were already down and fired at random directions. Some children and staff members managed to hide in various places trying to escape his gunfire.

Towards the end of his rampage, he briefly left the gym but then returned. He then took out one of the revolvers, put it in his mouth, and pulled the trigger, killing himself. In total, 32 people sustained gunshot wounds during the chaotic scene. Among them, 16 were fatally wounded in the gymnasium, including the teacher and 15 students. One more child died later in the hospital.

The police were notified of the incident around 9:41 a.m., and emergency services began arriving shortly after the first call. The first ambulance reached the school at 9:57 a.m. Many of the injured were taken to Stirling Royal Infirmary for treatment. Sadly, twelve of the children who were killed were buried in a memorial garden created in their honor at Dunblane Cemetery.