As a Los Angeles deputy district attorney, Lynn D. "Buck" Compton was known for heading the three-man team that successfully prosecuted Sirhan B. Sirhan for the 1968 slaying of U.S. Sen. Robert F. Kennedy.

And after then-Gov. Ronald Reagan appointed him to the 2nd District Court of Appeal in 1970, he was known as one of its most conservative jurists.

But it was long after he retired from the bench in 1990 that Compton became known for something that previously had been mentioned only in passing in newspaper articles about him: his World War II military service.

Compton was a first lieutenant in Easy Company, 2nd Battalion, 506th Parachute Infantry Regiment in the Army's 101st Airborne Division — one of the true-life characters who gained late-in-life renown when they were portrayed in "Band of Brothers," the 2001 HBO miniseries based on historian Stephen E. Ambrose's 1992 bestseller.

Compton, who suffered a heart attack Jan. 11, died Saturday at his daughter Tracy's home in Burlington, Wash., said his family. He was 90.

After parachuting into Normandy during the early hours of D-day in June 1944, Compton was part of the assault group that destroyed the German artillery during the battle at Brecourt Manor. He fought at Carentan, participated in Operation Market Garden in Holland and helped defend Bastogne during the Battle of the Bulge.

Before the war was over, he had been awarded a Silver Star and a Purple Heart

"Not too many people knew about his military heroics until the miniseries," said Tracy Compton.

As her sister Syndee put it: "His career as a prosecutor and a judge overrode his military career until 'Band of Brothers' came out, and then it just went crazy. Then it became more about him being in the military rather than his being a judge or a prosecutor."

Syndee Compton said her father was surprised by suddenly being in the spotlight.

"I think it probably shocked all of them," she said. "I don't think any of them in their wildest dreams thought at 80 years of age they'd be getting this attention."

In the years after "Band of Brothers," Compton was asked to speak at local schools and at military bases in Germany and South Korea.

He also continued to receive fan mail from around the world.

His family estimated that nearly 400 people showed up in January for a 90th birthday celebration for Compton at the Skagit Regional Airport in Burlington, including children of other "Band of Brothers" veterans.

"All I can say is it's flattering — and kind of embarrassing," the Skagit Valley Herald reported Compton as saying. "We didn't expect anything more than those other guys [in the war]. We're celebrating longevity more than anything."

The crowd included four actors from "Band of Brothers": Michael Cudlitz, James Madio, Richard Speight Jr. and Neal McDonough, who portrayed Compton in the miniseries.

McDonough recalled meeting with Compton in Burlington the day before he flew to London to begin filming "Band of Brothers" and later peppering him with "phone calls at all hours" with more questions about his time during the war.

"When you play a historical figure, you have to do it right and tell the truth," McDonough told The Times this week, recalling that Compton would tell him, "I didn't really do anything; I was just doing my job."

"He'd say that's what soldiers do," said McDonough, who kept in touch with Compton and nicknamed his 6-year-old son Morgan "Little Buck" in his honor. "He did extraordinary things in his life and never took credit for it."

Tracy Compton said her father thought McDonough "did a wonderful job" portraying him and that "he laughed and said Neal was better-looking than he ever was."

Compton was born in Los Angeles on Dec. 31, 1921. He majored in physical education and minored in education at UCLA, where he lettered in both football and baseball. (Jackie Robinson was a teammate in both sports.) Compton started at guard in the 1943 Rose Bowl game against Georgia and was selected all-conference catcher while captain of the baseball team in 1942.

He also participated in the ROTC program and entered active service in February 1943 at age 21.

After the war, he became a Los Angeles police officer and worked his way through Loyola Law School. He was a detective in the Central Burglary Division before joining the district attorney's office in 1951. He was assistant district attorney when Dist. Atty. Evelle J. Younger chose him as his chief deputy in 1966.

In his 2008 memoir "Call of Duty: My Life Before, During, and After the Band of Brothers," Compton said that prosecuting Sirhan, in many ways, "was the peak" of his career in the D.A.'s office.

During the prosecution's final summation, Compton termed the case "highly overcomplicated" by psychiatric expertise. And, according to a 1969 Times account, he told the jury that the psychiatric testimony had been so confusing and conflicting that "I can be frank to admit right now as I stand here that I can't answer the question of what Sirhan's real motive was."

But, he told the jury, if they "don't buy" the psychiatric testimony, "like I don't buy it, and like [deputy district attorneys] John Howard and Dave Fitts don't buy it — then there's nothing left but plain old cold-blooded first-degree murder."

Compton also dealt with a number of high-profile cases during his years on the 2nd District Court of Appeal, including a seminal 1983 case in California regarding life support in which two doctors were accused of murder for causing the death of a man in a coma.

The patient's condition was terminal and he would never have regained consciousness. With the wife's consent, the doctors removed the patient's hydration and nutrition system.

"These were," Compton noted in his book, "the days before living wills."

He and two other judges found the doctors not guilty of criminal conduct.

Compton's wife, Donna, died in 1994. Besides his two daughters, he is survived by four grandchildren.

dennis.mclellan@latimes.com

Lynn D Compton