Danny S. Shelley, 31, of Eubank, Ky., was charged with killing Pulaski County Sheriff Sam Catron.
Catron's father, Harold Lewis Catron Sr., was killed in the line of duty in 1964.
Lt. Lisa Rudzinski, a state police spokeswoman, said Catron was shot and killed Saturday in Shopville, Ky., by a high-powered rifle as he walked to his vehicle after giving a speech.
No one else was wounded in the shooting, she said. Shopville is located about seven miles east of Somerset.
Rudzinski said Catron finished his speech around 7:15 p.m. and was walking back to his car when a motorcyclist shot him before speeding away. He was pronounced dead at the scene, she said.
Shelley was stopped about five miles from the scene after he wrecked his motorcycle.
Police were unsure is the suspect and Catron knew each other. Catron, 48, appeared on a segment of "America's Most Wanted" Saturday about a militia fugitive, Steve Anderson, who shot at a police officer and fled into the mountains of Eastern Kentucky in October.
"We have no reason to believe it's connected," Rudzinski said.
Former County Attorney Fred Neikirk said Catron was a respected member of the community.
"Everyone in the county was a friend of his," Neikirk told Sunday's Lexington Herald-Leader. "I can't imagine someone murdering the sheriff just because he didn't like him."
Catron, a Republican who had been sheriff since 1986, was running for re-election. He was seeking a fifth term.
An autopsy by the state medical examiner was scheduled for Sunday in Frankfort.
Catron was single and lived with his mother. Other survivors include a brother and two sisters. Funeral arrangements were pending.