Ridgway was born in the mid 1900's in Salt Lake City, Utah. He was deemed to have had a troubled childhood growing up, he would have violent arguments with his family members growing up multiple times. As Ridgeway was growing up he had an IQ of 82 which meant he was below average intelligence. Gary's mother growing up was physically and mentally abusive towards him and his two brother's Gregory, Thomas Jr. and even her husband. His father was a bus driver that often complained about the prostitutes that were on his bus routes.
At the age of 16 Ridgway stabbed a young boy age 6 in the ribs through to the liver. The boy survived the stab but when Ridgway was walking away he admits that he said "I always wondered what it would be like to kill someone". Growing up he would shoot birds with BB guns and torture other animals. Ridgway said that he committed his first crime as a teenager at the age of 18. He wrapped his legs around a young boy and held him under the water until he drowned.