At a glance, you would never suspect Jerry Givens was once a state-sanctioned killer.

Key points: Last year, a survey found that 56 per cent of Americans support the death penalty

Last year, a survey found that 56 per cent of Americans support the death penalty Capital punishment is legal in 30 American states, and 1,498 Americans have been executed since 1976

Capital punishment is legal in 30 American states, and 1,498 Americans have been executed since 1976 One former executioner, Jerry Givens, is now on a mission to stamp out state-sanctioned killings

He is a deeply religious family man, who loves to laugh and sings in his church's choir.

But for 17 years he was the US state of Virginia's chief executioner, putting 37 men to death in the electric chair and killing 25 others with lethal injections.

The whole time, he was sworn to secrecy.

Even his wife didn't know he had calmly, methodically ended 62 lives.

"It's a big thing to carry inside," he says.

His family finally found out about his job when they picked up a newspaper and learned he had been accused of a crime.

"[The executions] will be with me as long as I live," Mr Givens said.

Today, Mr Givens is trying to spread his grisly story as far and wide as he can.

For more than a decade, he said, he has been on a mission from God to stamp out the punishment he once so methodically carried out.

The slow, yet steady, decline in the death penalty across America suggests to him he is helping win over hearts and minds.

An executioner's routine

Convicted murderers James Briley, Ricky Gray, Richard Lee Whitley and Roger Keith Coleman were all executed by Mr Givens. ( Supplied )

Two decades have passed since he last carried out an execution, but the procedure is still clearly imprinted in his mind.

The condemned would come into his care 15 days prior to their date with death and immediately undergo a complete physical examination to make sure they were healthy.

On their final day, family farewells were at 3:00pm, a last meal was served around 6:00pm and inmates took their last steps to the death chamber just before 9:00pm.

Mr Givens prayed with the condemned and focused on their needs.

Most confessed terrible crimes to him and were calm, he said — they had no idea he was the one who would end their lives.

"I think a lot of them were crying on the inside. None struggled, " he said.

Mr Givens put 37 men to death in the electric chair before lethal injection was introduced in 1994. ( Supplied: Jerry Givens )

When the inmates were strapped to the electric chair or padded gurney, they were given a chance to utter a few final words.

The prison warden would then give a signal, such as a flick of his glasses, and Mr Givens would swing into action.

"When it comes down to pushing that [electric chair] button, the only thing you could hear was the machine humming," he said.

"But when it comes down to lethal injection you got the syringe in your hand and you're watching the chemicals go down in a plastic tube into his arm. You feel more attached."

If he had to be executed, Mr Givens said he would choose the electric chair — because it's quicker.

The journey to anti-death penalty advocate

Mr Givens (left) started his career as a corrections officer in the 1970s. ( Supplied: Jerry Givens )

Mr Givens started his career as a prison guard and volunteered to assist in putting people to death.

Then, when the chief executioner retired, he stepped into the role.

Mr Givens said sometimes electrocutions would cause nosebleeds, particularly if the mask was not properly put on.

He said it was also sometimes difficult to find veins large enough on former drug users to administer a lethal dose via an injection.

"There's no perfect painless way to take someone's life," he said.

He claimed an execution never went badly on his watch, though several he carried out are listed as "botched" on the Death Penalty Information Centre's website.

Yet as his career progressed, major doubts began to emerge.

'Once there's doubt, you can't get rid of it'

It was ultimately the exoneration of Earl Washington — a death row inmate with the IQ of a 10-year-old child — that eroded Mr Givens' support for capital punishment.

Mr Washington was just nine days away from execution for the rape and murder of a Virginia woman before doubts were raised about his involvement in the crime.

DNA evidence cleared him, and he was later freed.

"Once there's doubt, you can't get rid of it," he said.

Mr Givens wanted to stop, and planned to stand down once he had carried out 100 executions.

But his career ended before that milestone when he was forced to resign in 1999, after being charged with money laundering and lying by a grand jury.

A stint in prison and renewed commitment to religion inspired Mr Givens to campaign against capital punishment. ( ABC News: Emily Olson )

Mr Givens — who still maintains his innocence — had bought cars on behalf of a childhood friend, a former drug dealer, who he thought had changed his ways.

A stint behind bars helped transform the executioner to an anti-death penalty advocate.

He said he realised capital punishment was not consistent with God's teaching, and decided the Lord wanted him to spread the word.

The death penalty in decline

The campaign against the death penalty in the US is continuing to gain traction.

In 1999, 98 people were put to death, but so far this year just eight have faced the needle.

Twenty states have abolished capital punishment, and New Hampshire seems likely to become the 21st.

California, which has the most people currently on death row in the country, recently announced a moratorium and removed equipment from its execution chamber.

"We're seeing one by one, states move away from the death penalty," Robert Dunham, the executive director of the Death Penalty Information Centre said.

"On a country level too, prosecutors are pursuing it less frequently."

Mr Givens' state of Virginia is a good example.

It has a long history of executions — the first took place in the Jamestown colony in 1608.

Since 1976, it has carried out 113. Only Texas has put more people to death — 561 in total.

But just three people now remain on Virginia's death row, and there hasn't been a capital sentence handed down since 2011.

'I take no joy or satisfaction from it'

Prosecutor Paul Ebert believes the death penalty deters violent crime. ( ABC News: John Mees )

Not everyone is pleased by the trend.

Prosecutor Paul Ebert has sent 15 people to Virginia's death row, more than anyone else in the state, over a career spanning more than half a century.

He believes the ultimate penalty deters violent crime, but said opposition to it has made it harder to pursue — and has also made it more difficult to convince a jury to sentence someone to die.

"You've got more and more money spent by the defence and less assets for the prosecution. That's one big thing," the Prince William County Commonwealth's Attorney said.

Mr Ebert's biggest courtroom victory was the death sentence given to the man known as the DC sniper, John Allen Muhammad.

Muhammad and his partner randomly shot people around the Washington DC area, terrorising the US capital over a three-week period in October 2002.

The DC snipers shot people at random in 2002 while hiding in the boot of this car. ( Reuters: Brendan McDermid )

Mr Ebert, who was elected to his role 13 times as a Democrat, said he had no doubt the mass murderer deserved a lethal injection.

"I've had several people that did not believe in the death penalty until they lost a loved one. Then suddenly they could see a need for it," he said.

"I take no joy or satisfaction from it. We have laws and punishments supported by the people and they should be followed and carried out after a fair trial."

Surveys consistently show that a majority of Americans are in favour of the death penalty.

A Gallup Poll in 2018 put overall support at 56 per cent — down from 80 per cent in the mid-1990s.

President Donald Trump is strongly in favour of it and the nation's highest court, which has a conservative majority, is unlikely to strike it down nationwide any time soon.

Virginia prosecutor Paul Ebert sought and won the death penalty for the DC sniper. ( ABC News: John Mees )

So, for the foreseeable future, prosecutors in 30 American states will continue to face a choice for the worst cases — should they ask for death or not?

"The defence counsel always says it's far worse to be imprisoned for life than face the death penalty," Mr Ebert said.

"But the accused always have the option of choosing death — and they don't."

The executioner's suffering

Mr Givens put 62 people to death during his career as an executioner. ( ABC News: Emily Olson )

Mr Givens, who has been both jailer and prisoner, disagrees.

"The guys … on death row would say to me, 'you constantly die every day sitting on death row,'" he said.

So, does he now regret his role in killing 62 people?

"No," he said.

"Sixty-two sets of eyes that I closed are gone, but what's left open are the eyes of billions who I can talk to these things about."

"If a condemned man gives himself to Christ and asks for forgiveness, this is not the end for him. This is only the beginning. He don't have no suffering," he said.

"Those who have to suffer are those you leave behind, including the executioner."