Image copyright Getty Images Image caption Air force Sgt Cronauer spent most of his life in broadcasting, before Hollywood depicted his life

Adrian Cronauer, who served as inspiration for Robin Williams' breakout character in the 1987 film Good Morning, Vietnam, has died in Virginia aged 79.

Like his eponymous character, Cronauer was a radio presenter in Saigon in 1965 and 1966 known best for his enthusiastic early morning greeting and penchant for playing rock'n'roll tunes to raise American troops' morale during the Vietnam War.

But Hollywood took a lot of liberties in its depiction of the air force sergeant.

Cronauer was born in Pittsburgh, Pennsylvania, in September 1938, to a steelworker father and teacher mother.

Image copyright Getty Images Image caption Williams was nominated for the Best Actor Academy Award for his depiction, but lost to Michael Douglas

A keen broadcast fan throughout his life, he landed a semi-regular slot on local children's television aged just 12.

After enrolling in his home city's university in the 1950s, he helped found a student radio station and worked with local broadcasters throughout his studies in Pittsburgh and later in Washington.

'Goooood morning Vietnam!'

Cronauer joined the US air force, doing his training in San Antonio and Wichita Falls, Texas. His first deployment was to the island of Crete in Greece - where he spent a year-and-a-half and developed his signature radio greeting.

He told the Fayetteville Observer in 2011 that his initially timid "Good Morning, Iraklion" gradually became "wilder and wilder" into the dramatic, booming and protracted form he would become notorious for in Vietnam.

Keen to travel, Cronauer says he actually volunteered for a transfer to Vietnam, where he was hired initially as a news director for Armed Forces Radio there.

After his morning presenter left, he took up the 06:00 Dawn Buster show mantle, greeting troops with an enthusiastic yell of: "GOOOOOOOOD morning, Vietnam!"

Image copyright Getty Images Image caption Unlike the Hollywood version, the real Cronauer denied having a specific love interest

Cronauer soon found out while interviewing troops that his ironic salute was often met with "the GI equivalent of: Get stuffed Cronauer" on bad days, he recounted at a veterans event in 2008.

"On one occasion, a guy picked up his M16 and blew away his radio," he told the Americans Veterans Centre conference.

The famous greeting would be adopted by the show's presenters after him.

More lives in profile:

Cronauer shunned traditional favourites and shelved them for music of the time: treating US troops to jams from the Righteous Brothers, Tom Jones and the Beatles.

He told the Fayetteville Observer he wanted to serve as an antidote to the homesickness and culture shock affecting thousands of young American men over in Vietnam, who in their teens and twenties had been picked up and "dumped in a totally alien environment".

"The crowning achievement for me was when I heard from some guys that when they tuned into Dawn Buster for the first time, they assumed they had picked up some radio station from the States," he would tell the Chicago Tribune.

Image copyright Getty Images

But Cronauer was never the local celebrity or subversive that late comedy star Robin Williams made him out to be.

The role instead became a showcase for the frenetic Williams, who ad-libbed much of the broadcast depictions.

Williams acknowledged that the real-life Cronauer was not the "radio desperado" he portrayed.

"In real life he never did anything outrageous. He did witness a bombing in Saigon. He wanted to report it - he was overruled. He didn't want to buck the system, because you can get court-martialled for that," Williams told Rolling Stone magazine.

Cronauer was keen to point out the drastic changes: "There's a lot of Hollywood exaggeration, and outright imagination."

Like the film character, he did teach English when off-duty, but did not indulge in teaching locals American crudities or New York street slang. He was never in a jeep that got hit by a landmine, nor did he ever get lost in the jungle trying to escape the Vietcong.

After being honourably discharged after his prescribed year, he returned to the US, where he met juvenile probation officer Jeane Steppe while doing local community theatre. They married in 1980 and moved to New York, where he gained a master's degree in communications and picked up voice-over work in television and radio commercials.

Image copyright Getty Images Image caption Cronauer said many veterans assumed it was him they had heard in Vietnam, after other broadcasters adopted his signature greeting

He and friend and fellow Vietnam-veteran Ben Moses initially touted the idea of a Vietnam War-themed sitcom along the lines of M*A*S*H together.

They then re-wrote the story as a television movie after watching Apocalypse Now.

"We said that's not our story of Vietnam," Mr Moses told the Associated Press on Thursday.

The project stalled because of Hollywood's hesitancy to produce a comedy about the painful and extremely divisive and conflict.

Eventually, the script ended up with Robin Willliams' agent. The comedian thought a disc jockey was the perfect role for him to play-up to all his "comic shtick", the New York Times reports.

It then became heavily fictionalised, re-fashioned for the big screen under the directorship of Barry Levinson and writer Mitch Markowitz.

Williams' breakthrough

The role of Cronauer transformed Williams into a household name and earned him an Academy Award nomination. The pair were purposefully kept apart during production, allowing Williams free rein.

"When the movie premiered in New York, we met, and we shook hands and Robin said, 'I'm glad to finally meet you.' And I said, 'Well, I'm glad to finally meet me, too," Cronauer would recount to the Roanoke Times newspaper.

The movie earned him a level of celebrity, and he said he was once asked for an autograph by actress Bette Middler. He spoke affectionately about Williams' performance in interviews.

Cronauer would joke that "Vietnam DJ" would end up etched on his tombstone, but he used his earnings from the film to attend law school, going on to open a communications practice and even work at publishing a textbook.

Politically he was far from an actual "anti-establishment type" - describing himself as a "life-long, card-carrying Republican".

In 1992, he featured in a television advert for George HW Bush, attacking Democratic opponent Bill Clinton on the draft.

Cronauer remained a prominent part of the broadcasting and veteran communities throughout his life and from 2001 to 2009, served as a confidential adviser to the US deputy assistant secretary of defence.

He would receive the Secretary of Defence Medal for Exceptional Public Service, and remained as a prominent member of the community, supporting theatre, broadcast and veterans groups.

He lived his last years in Troutville, Virginia. His wife Jeane died in 2016. Family members confirmed he had died aged 79 on 18 July in a nursing home.

The veteran is survived by a stepson, daughter-in-law, four grandchildren and two great-grandchildren.