Sam Bankman-Fried speaks from his jail cell for the first time since being sentenced to 25 years in prison

Disgraced former crypto billionaire Sam Bankman-Fried said that he didn't think what he was doing was illegal in his first interview in the aftermath of his sentencing for fraud last week.

'I never thought that what I was doing was illegal. But I tried to hold myself to a high standard, and I certainly didn't meet that standard,' Bankman-Fried, 32, told ABC News from his jail cell in Brooklyn.  

Bankman-Fried was sentenced Thursday to 25 years in prison for a massive fraud on hundreds of thousands of customers that unraveled with the collapse of FTX, once one of the world's most popular platforms for exchanging digital currency.

As he was sentenced Thursday after being convicted of seven counts of fraud, conspiracy and money laundering, the judge said that the defendant's remarks never conveyed 'a word of remorse for the commission of terrible crimes.' 

But the former poster boy of cryptocurrency has now insisted that he is 'of course' remorseful for his actions, saying via email that what happened still 'haunts' him and that 'it's most of what I think about each day.'

Bankman-Fried spoke over the weekend from his cell in the Metropolitan Detention Center in Brooklyn.

During his correspondence with ABC, he admitted that FTX's insolvency was the result of several 'bad decisions' he made in 2022.

'I'm haunted, every day, by what was lost. I never intended to hurt anyone or take anyone's money. But I was the CEO of FTX, I was responsible for what happened to the company, and when you're responsible it doesn't matter why it goes bad. 

'I'd give anything to be able to help repair even part of the damage. I'm doing what I can from prison, but it's deeply frustrating not to be able to do more,' he said. 

More than 1 million customers face potential losses as a result of FTX's sudden November 2022 collapse. 

Victims say they are still owed more than $19 billion based on current crypto prices - though Bankman-Fried insisted during his sentencing that victims can get their money. 

Judge Lewis Kaplan recommended a medium-security jail for Bankman-Fried's sentence and ordered him to pay $11billion for stealing $8 billion from customers in an elaborate scheme.

Bankman-Fried has vowed to appeal his sentence, and said his defense team will do so later this year based on certain testimony in his trial that he said, 'greatly misstated what actually happened'.

He pleaded for a more lenient sentence at New York City federal court on Thursday.

'A lot of people feel really let down and they were very let down. I'm sorry about that. I'm sorry about what happened at every stage,' Bankman-Fried he said. 'Things I should have done, things I shouldn't have.'