U.S. President Donald Trump commuted the sentence Wednesday of a woman serving a life sentence for drug offences whose cause was championed by reality TV star Kim Kardashian West in a recent visit to the White House.

The White House released a statement announcing the commutation of Alice Marie Johnson. The 63-year-old grandmother has spent more than two decades behind bars and is not eligible for parole.

The move comes amid a recent flurry of pardons issued by Trump, who has seemed drawn to causes advocated by conservatives, celebrities or those who once appeared on his former reality show The Apprentice. This use of executive power is taking place against the backdrop of the Russia investigation that hangs over his presidency.

The White House said Johnson "has accepted responsibility for her past behaviour" and has been a model prisoner, working hard to rehabilitate herself and serve as a mentor to fellow inmates. It said that Johnson's warden, case manager, and vocational training instructor had written letters in support of her clemency.

Johnson, 63, is seen in an undated photo posted on her daughter's Change.org petition page. (Change.org)

"While this administration will always be very tough on crime, it believes that those who have paid their debt to society and worked hard to better themselves while in prison deserve a second chance," according to a statement from the office of White House spokesperson Sarah Huckabee Sanders.

Johnson's daughter Tretessa Johnson declared "victory" on her Change.org petition page, which had more than 271,000 supporters, and posted a note on Facebook thanking everyone involved.

Kardashian West visited the White House last month to meet with Jared Kushner, Trump's son-in-law and senior adviser, who is overseeing the administration's push to overhaul the nation's prison system. She also met with Trump in the Oval Office, a photograph of which the president released on Twitter.

On Wednesday, Kardashian West expressed gratitude for the decision in a message on Twitter.

So grateful to <a href="https://twitter.com/realDonaldTrump?ref_src=twsrc%5Etfw">@realDonaldTrump</a>, Jared Kushner & to everyone who has showed compassion & contributed countless hours to this important moment for Ms. Alice Marie Johnson. Her commutation is inspirational & gives hope to so many others who are also deserving of a second chance. —@KimKardashian

The commutation puts a renewed focus on the Trump administration's push for prison and sentencing reform, but which has sometimes clashed with the president's law-and-order approach, especially at the Justice Department. Indeed, Trump has called for getting tougher on drug dealers, including suggesting some should receive the death penalty.

Johnson was convicted in 1996 on eight criminal counts related to a Memphis-based cocaine trafficking operation involving more than a dozen people. The 1994 indictment describes dozens of deliveries and drug transactions, many involving Johnson.

Decades-long legal fight

She was sentenced to life in prison in 1997, and appellate judges and the U.S. Supreme Court have rejected her appeals. Court records show she has a motion pending for a reduction in her sentence, but federal prosecutors are opposed, saying in a court filing that the sentence is in accord with federal guidelines, based on the large quantity of drugs involved.

The U.S. Attorney's Office in Memphis did not immediately respond to a request for comment Wednesday afternoon.

A criminal justice advocacy site, CAN-DO, and one of Johnson's attorneys said a request for clemency was rejected by former president Barack Obama. The reasons are unclear.

A 1997 Associated Press story on Johnson's sentencing said she headed up a multimillion-dollar drug ring. But Memphis attorney Michael Scholl, who filed the latest court documents in her request for a sentence reduction, said she was not a leader in the cocaine operation.

"What is the purpose of putting a lady with no prior criminal record, on a non-violent drug offence, in jail for her entire life?" he said in a telephone interview. "She's a model inmate."

Scholl added that Johnson has admitted her wrongdoing, which is borne out in letters she has written to U.S. District Judge Samuel H. Mays, who now oversees her case.

"Judge Mays I'm writing to you to express my deep remorse for the crime that I committed over 20 years ago. I made some bad choices which have not only affected my life, but have impacted my entire family," she said in a February 2017 letter in the court record.

In a hand-scrawled letter last June she wrote: "I'm a broken woman. More time in prison cannot accomplish more justice."

'2nd chance at life'

In an interview released earlier this year, Kardashian West said earlier this year she'd been moved by Johnson's story after seeing a video on Twitter.

"I think that she really deserves a second chance at life," Kardashian told Mic. "I'll do whatever it takes to get her out."

Johnson's commutation comes days after Trump pardoned conservative commentator Dinesh D'Souza, who was convicted of a campaign finance violation, and granted a posthumous pardon to boxing's first black heavyweight champion, clearing Jack Johnson's name more than 100 years after what many saw as a racially charged conviction.

The boxer's pardon had been championed by actor Sylvester Stallone, who Trump said had brought the story to his attention in a phone call.

Trump has also pardoned:

Former Maricopa County sheriff Joe Arpaio, a staunch campaign supporter.

Scooter Libby, who served as chief of staff to vice-president Dick Cheney.

A U.S. navy sailor convicted of taking photos of classified portions of a sub.

In May, he also suggested he was considering acting to commute the sentence of former Illinois governor Rod Blagojevich, a former Celebrity Apprentice cast member who is serving 14 years in prison for corruption, and celebrity homemaker Martha Stewart, convicted of making false statements to federal investigators.