Meet Kevin Costner's parents, his lesser-known sibling and discover their family tragedy

Kevin was raised by a family of staunch Baptists who held conservative views, according to the actor. They are descended from German immigrants, and he also boasts English, Irish and Scottish ancestry. 

According to Kevin's father, William, he grew up a precocious child and always went after what he wanted. "From day one, Kevin was his own person," he recalled to Time in 1989. "Once he decided to take charge of organizing a parade at his school."

"I figured it was too big a job for an eleven-year-old and said, 'Kevin, you can't do that.' And Kevin said, 'Dad, never tell me I'm not able to do something.' He went ahead and organized the parade."

Kevin was a sporty child and only considered acting as a career in his final year of college. 

Kevin grew up in Compton, California, and is the youngest son of William and Sharon Costner. William was an electrician and utilities executive, and his job took the family all over the United States. 

Kevin told GQ in May this year about the impact that constantly moving for his father's job had on him growing up. "I lost a lot of confidence in those years, and almost lost myself," he revealed. 

Despite this disconnect, Kevin remained close to his father even after moving away to college. He told The Hollywood Reporter that William always "took a big interest in my career", even offering unsolicited advice about his smash-hit television show Yellowstone.

According to the actor, his father told him, "'You're gonna lose your audience, fella. That is a naughty show. They're gonna drift away son…You mark my words that's naughty.'"

The Dances With Wolves actor continued, "I just look at my dad and say 'Oh my God.' And a few years later he goes 'The nurses wanna know how it ends.'" 

Kevin's dad even got involved in some of his projects; he revealed on the Late Late Show with Craig Ferguson in 2014 that William jumped at the chance to feature in a film. 

"In Dances with Wolves, when I'm actually riding, I'm about to give up my life, and I do that Catholic thing, and then the soldier who's about to shoot me gets shot in the forehead. He does that and I cut back, and it's my father with the gun."

"I said, 'You want to be in the movie, you want to save me?' and he said, 'Yeah.' There's little things that you can throw people into," he concluded. 

Sadly, William has since passed; but Kevin credits his father for imposing a strong work ethic on his children. "He was tough," he told The Hollywood Reporter. "He was a fighter; he could fight. And he taught me in a way that was designed to win." 

Kevin also remained incredibly close to his mother, Sharon Costner, until her death just seven months after losing William.

She was a welfare worker, and just like her husband, Sharon fiercely supported her children in their endeavours.

"My parents followed me…they saw my little league games and everything," Kevin told Craig Ferguson on the Late Late Show. The pair were so passionate about their son's blossoming career that they even followed him onto a film set to watch over him, according to the 69-year-old. 

"When I went out to direct a movie, they got a trailer and took it out to South Dakota," he began. 

"They go, 'We won't be in your way, we'll be on a hill over here and we'll watch you' and it was like, 'I'm a grown man.'"

"I would look up on the hill in the morning, and they had two lawn chairs and a motor home, and I go work with all the guys, and I see my mom wave at me, and I [wave] to my mom."

Sharon gave birth to three children, including Kevin; sadly, she and William lost their son, Mark Douglas Costner, just days after his premature birth in 1953. He is buried in Whittier, California. 

The couple also shared another son, Daniel Craig Costner, who remains close to his brother Kevin.

Daniel and Kevin reportedly grew up close despite their five-year age gap, as they were the only siblings in the Costner household. He maintains a private life out of the spotlight and worked in oil separation technology to minimize the impact of oil spills. 

The brothers worked together after Daniel left a lucrative executive role to join Kevin's company, Tig Productions, which produced box office hits like The Bodyguard and Dances With Wolves. 

Daniel oversaw finances at the company and told Time in 1989 that he was glad he had left his previous job for his brother. "You wouldn't do this unless it was your brother, and you wouldn't do it unless your brother was Kevin."

Kevin turned down a huge role in Oliver Stone's 1986 film Platoon for his brother, he revealed to Time. The father of seven said, "I didn't even meet with [Stone] because my brother Dan had been in Vietnam, and I was reluctant to do a film about something that had such an impact on his life."

He continued, "In a way, I regret not doing it; it was a wonderful film. But my consciousness was with my brother." Kevin told GQ that while he was firmly against the war, being in a conservative family meant that he "couldn't talk out" against it. 

"I started to write a whole book about my brother in Vietnam," he told the publication. "I mean, I started and stopped." Daniel, now 74, won a Navy and Marine Corps medal for heroism during his time in Vietnam.