He's one of Hollywood's most celebrated filmmakers, has worked with Sean Connery, Bruce Willis and Samuel L Jackson, and grossed hundreds of millions at the box office. And he is now serving a 12-month jail sentence in South Dakota.

John McTiernan, the director and producer of Predator, Die Hard, The Hunt For Red October and Last Action Hero, is now federal penitentiary prisoner 43029-11.

It's a spectacular fall from a stellar Hollywood career that made him a fortune to remote Yankton prison.

Instead of being in a director's chair on the set of a new movie, the 62-year-old is wearing khaki prison uniform, engaged in a series of relatively modest jobs, from unloading deliveries to renovating the warden's wooden floor.

He is two months into a 12-month prison sentence for perjury and lying to the FBI during an investigation into a wiretapping scandal. It is a convoluted case, involving a dispute over a remake of the movie Rollerball, the employment of a Los Angeles private eye and, the crux of the case, a late-night call from an FBI agent.

In a series of phone interviews with the Guardian, his wife Gail Sistrunk McTiernan, fighting for his release, spoke in detail about the impact of loss of freedom. Unlike the tough guys he portrayed in his movies, he is not coping well with adversity.

Yankton is a minimal-security prison, based in former college buildings, and houses about 800 male prisoners, many of them convicted of white-collar crimes. Forbes rated it one of "America's 10 cushiest prisons".

But McTiernan is finding it to be anything but cushy, according to his wife. "Going to prison has been very hard for him," she said. "They have taken away his life and dignity. I am just distraught."

Her last visit, at the end of May, was one of the worst. "I lost count of the number of times he broke down," she said. He is "disintegrating in front of my eyes".

McTiernan went in on April 3. He and his wife were driven through the night from their ranch in Dayton, Wyoming, to make the midday deadline, engaged in feverish discussion with their lawyer, hoping for a last-minute reprieve.

Sistrunk McTiernan said: "We thought we would not make it in time and the marshals would come after us. It was typical McTiernan to arrive at the noon-day horn." She said he turned to her and told her: "Do what you have to do, baby." He told her that she should leave before they took him away. "I would not have handled it very well," she said.

He had hoped for a teaching job in prison but instead has been assigned to a construction and maintenance crew.

He is in a barracks, shared with about 20 others. "He is grateful he got the lower bunk. I think the older men get the lower bunk because they have to get up in the middle of the night," she said.

An avid reader, McTiernan is allowed books, magazines and papers and she sends in the New York Times, along with the Economist, Rolling Stone, and National Geographic, along with history and engineering magazines. A French fan, maybe ironically, sent him a copy of the Count of Monte Cristo.

One of Sistrunk McTiernan's fears had been that her husband might have ended up the victim of extortion threats, with calls to her demanding money or he would be harmed. But there have been no such threats and the inmates have largely left him to himself.

Her main worry is the threat is to his mental and physical health. He has lost 30lbs and is suffering from depression, she said, adding that he weeps on the phone and during her visits. To offer a glimpse into his mood, she shared what she said was a recent email from him.

Describing fellow inmates, the email says: "People's faces change very rapidly. One frame in 10 will look completely different. That's why professional photographers shoot so many frames … because the face will change so rapidly … faster than human beings can perceive it.

"I'm starting to see those ghost frames. the frames where the person's face shows what he really thinks. There are many men here so close to dying."

She said she planned to email him back, "offer a prayer and encouragement (also feel a fool to try), and make sure he's not looking in the mirror".

While the comings and goings from rehab or prison of other celebrities receive primetime coverage, McTiernan has been largely forgotten.

Buzzfeed carried a piece last month but otherwise media attention has been sparse.

It may be because McTiernan, consumed with the legal case, has not made a box-office movie in over a decade. It may be the legal case has been prolonged and complex. Or it could just be that the national media regards him as soiled goods because of his conviction.

The case dates back to 2002, when McTiernan, directing a remake of the Norman Jewison sci-fi classic Rollerball, was in disagreement with the producer Chuck Roven about what kind of movie it should be. McTiernan hired Anthony Pellicano, a private investigator used by by Hollywood celebrities, to check on Roven.

Pellicano was subsequently sentenced to 15 years for a series of crimes that included racketeering, conspiracy and wiretapping.

In the course of that investigation, McTiernan's name came up. In 2006, McTiernan took a call at his ranch late at night on February 13 from a man who said he was from the FBI. McTiernan denied hiring Pellicano to spy on Roven and was later arrested, accused of lying.

He pleaded guilty in 2006 and then withdrew it. He was convicted in 2010 of lying and perjury.

His wife sees the case as overblown, being branded a felon because he denied something over the phone to a man he did not know. She added that Pellicano had never conducted any wiretaps on behalf of her husband.

But the prosecution had little sympathy, seeing McTiernan as someone who was caught lying and has since desperately tried everything to get out off doing time.

There is a Free John McTiernan campaign on Facebook. It says:" Let's show our support to one of the greatest storytellers of our time." Actors such as Samuel L Jackson and Alec Baldwin have joined the campaign.

Sistrunk McTiernan said her husband plans to revive his career on his release. One under consideration is an action movie called Warbirds.

He is not scheduled for release until April next year because one of the stipulations in his sentence was that he would not be given time off for good behaviour.

Sistrunk McTiernan hopes he will not have to wait that long. There is a motion to have him released early. For her, it cannot come too soon. "I am intensely worried about him," she said.