Watch CNN's original series, "The Hunt," with John Walsh, Sunday nights at 9 p.m. ET on CNN.
(CNN) -- The man now synonymous with hunting bad guys had no intention of a career catching fugitives.
John Walsh was a hotel developer in south Florida, living a seemingly idyllic life with his wife and son, when a horrific tragedy changed his life -- and the lives of thousands of strangers.
Here are five things to know about the host of CNN's The Hunt with John Walsh:
1. His son was kidnapped and killed
Walsh's life unraveled in 1981 when his 6-year-old son, Adam, was abducted from a mall near their home in Hollywood, Florida.
Two weeks after Adam's disappearance, his severed head was discovered in a canal 120 miles away from the mall.
The devastation led Walsh to dedicate himself to catching fugitives and seeking justice for crime victims.
2. Helping nab the bad guys is his mission
For more than a decade, Walsh was known as the host of America's Most Wanted -- a groundbreaking show that put fugitives' profiles in the national spotlight.
The FBI credits America's Most Wanted for leading to the capture of 17 of the fugitives who have appeared on the agency's 10 Most Wanted list.
Walsh says 1,200 suspects have been caught as a result of the show.
What was one of his best gets?
Walsh says he accomplished in three days what the FBI couldn't do in 18 years: finding and capturing murderer John List, who killed his wife and three children.
3. He's a co-founder of the National Center for Missing and Exploited Children
Before Adam Walsh's kidnapping and death, there was no national database on missing children. Law enforcement officers could enter information on stolen cars, stolen guns and stolen jewelry -- but there was no central place to keep information on missing children.
So John Walsh and his wife Reve pushed Congress to pass the Missing Children Act, which led to the creation of the National Center for Missing and Exploited Children.
According to its website, the center has helped law enforcement find more than 196,000 missing children since it was founded in 1984.
"Our recovery rate for missing children has grown from 62 percent in 1990 to 97 percent today," the center says.
The site isn't just for law enforcement officers and missing children's families. At least one young woman discovered she was abducted as a newborn by using the database.
Carlina White, now 27, knew something was amiss when the woman who claimed to be her mother didn't resemble her and couldn't provide her birth certificate. So she logged onto the National Center for Missing and Exploited Children and found what turned out to be her baby picture -- eventually solving her own kidnapping.
After reading about White's case, a Philadelphia man who was adopted from an orphanage also searched the database and found a baby photo of himself. His father had reported him missing three decades earlier.
4. Elizabeth Smart's family counts Walsh among her rescuers
After her abduction at age 14, Elizabeth Smart was held captive for nine months. She was starved, threatened, tortured and raped on a daily basis.
While she was missing and her family searched for answers, her father Ed Smart turned to Walsh.
"He said, 'Be straight with me. Tell me what the odds are. You're the one guy who can tell me the truth,'" Walsh told CNN in 2010.
"And I said, 'You know what Ed, 99% of the cases I do have a very unhappy ending. You're lucky to find the remains, if you do.' "
But Walsh put a photo of Elizabeth's suspected kidnapper on America's Most Wanted. Days after watching the show, a woman spotted the suspect in suburban Salt Lake City.
5. Walsh also has a connection to the Ariel Castro case
For roughly a decade, Ariel Castro kept three young women captive in his Ohio home, abusing and raping his victims in what became known as the "house of horrors."
Walsh profiled two of the missing women -- Georgina "Gina" DeJesus and Amanda Berry -- several times on America's Most Wanted.
In a bizarre twist, it was Castro's daughter Arlene who appeared on the show to appeal for help in finding her friend DeJesus -- unaware that her father was actually hiding and abusing DeJesus in his home.