Frank Strada, commissioner of Tennessee's Department of Correction, will step down this month, while an independent review determines what happened on Wednesday, state governor Bill Lee said on Saturday.
Pike, 50, was given two doses of pentobarbital, a lethal drug used by Tennessee in state executions.
She was later taken to hospital, where she is on a ventilator and unconscious, her attorneys said.
In a statement, Mr Strada said that resigning was "in the best interest of Tennesseans" while an independent review - ordered by the governor - determines what happened when the state failed to execute Pike.
"I believe this review is entirely appropriate and necessary, and I look forward to doing everything I can to help determine exactly what occurred," he added.
Resignation does 'nothing' for Pike: Attorneys
Pike's legal team welcomed Strada's departure but said "it does nothing to help Christa now", adding: "What happened to her Wednesday reflects a systemic failure that goes far beyond any one person.
"We hope the governor's call for a full, independent review will expose the profound problems within Tennessee's entire death penalty system."
Attorneys said they believed problems with the IV lines caused the pentobarbital to flow into Pike's body instead of her bloodstream.
Mr Strada took over the department in January 2023 after serving as deputy director of the Arizona Department of Correction.
In late 2024, he announced that Tennessee was changing its lethal injection protocol and would use only pentobarbital.
Four people have been executed in Tennessee since 2025, according to the Department of Correction.
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Pike and her boyfriend, Tadaryl Shipp, were convicted of torturing and killing Colleen Slemmer, a 19-year-old classmate of theirs, at a job training facility in the city of Knoxville in 1995.
Prosecutors said Pike, who was 18 at the time, feared she was trying to steal her boyfriend, and lured her to a wooded area.
A pentagram, a star-shaped symbol associated with Satanism, was carved on the victim's body, which, along with other elements of the crime, stoked fears of Satan worship during the so-called "satanic panic" in the country during the 1980s and 1990s.
Shipp, who was 17 when the crime was committed, received a life sentence with the possibility of parole.
Pike does not deny the killing, but her supporters have argued the state should consider her age at the time, mental illness and a history of severe sexual abuse, including rape, beginning when she was a child.
Second failed execution this year
Pike's failed execution was the second such incident in Tennessee this year: In May, the execution of Tony Carruthers, convicted of killing three people in 1994, was called off after officials could not find a suitable vein for his lethal injection.
Last October, the lawyer of convicted child killer Byron Black claimed that he showed signs of "sustained cardiac activity" two minutes after he was pronounced dead following his execution in the state.
Concerns had been raised that Black was being put to death with a working defibrillator implanted in his chest.
Officers were called just before 7.50pm on Friday after members of the public reported hearing multiple shots fired in East Acton, the Metropolitan Police said.
The man was treated by London Ambulance Service, but died at the scene "despite the best efforts of medical staff", the force said.
Around 40 to 50 people, including children, were gathered for a memorial service, according to police.
The incident happened at the junction of Braybrook Street and Erconwald Street.
Detective Chief Inspector Brian Howie said: "Our thoughts are with the family and friends of a man whose life was taken in a senseless act of violence.
"We understand a large number of people had gathered for a memorial service, and what should have been a time to come together in remembrance has instead left a family devastated.
"We believe between 40 and 50 people, including children, were present when this incident occurred. Someone knows what happened and we need them to come forward."
No arrests have been made, police added. A police cordon remains in place in Braybrook Street.
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DCI Howie added: "If you were around Erconwald Street, Braybrook Street, the surrounding roads or Wormwood Scrubs playground between 6pm and 8pm, please think carefully about what you saw.
"Did you see anyone carrying or concealing weapons, people on bicycles acting suspiciously, or vehicles being driven at speed?
"We also want to hear from anyone with photographs, video, dashcam, doorbell or mobile phone footage or who has seen anything relevant on social media.
"However insignificant it may seem, the smallest piece of information could prove crucial in helping us establish what happened and identify those responsible."
The victim's family have been informed and are being supported by specialist officers, the Met said.
The demonstrations also follow the failure of the government to pass emergency legislation to help renters.
Prime Minister Pedro Sanchez had sought to ban evictions of vulnerable tenants until 2030, impose a two-year rent freeze extension for existing leases and introduce tighter rules for short-term rentals.
The opposition argued that the proposals, which were rejected in parliament on Friday, would exacerbate matters by reducing housing supply.
On Saturday, demonstrators demanded action on housing, and some called for a general strike.
"It's a shame," said Nando de Anguulo, 26, who joined the protest in Madrid.
"It only proves that it is us, the people, who have to adapt to the political parties, and not the politicians to what the people want, and this can't go on like that."
Mr Sanchez may call a snap election for November after the legislation failed to pass, Spanish media reported after his legislation was struck down.
However, Mr Sanchez's office refused to comment on the reports.
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In Valencia, demonstrators clashed with police, who fired rubber bullets and tear gas to break up protests.
Around 30 protesters got inside the City of Arts and Sciences, a landmark cultural building in the city, before they were removed by police.
Other demonstrations in 50 Spanish cities were peaceful.
About 70,000 protesters took part in the demonstration in Madrid, the Spanish government said on Saturday.
Ms Abascal was removed from her home in Madrid last month after being given just 30 minutes to leave the property with only essential belongings.
The apartment, in the capital's affluent Retiro neighbourhood, had been acquired by an investment fund that wanted to sharply increase her rent.
Ms Abascal, a wheelchair user, was taken to hospital on a stretcher following her eviction. She has since been told she can return to the apartment she had lived in for decades, her lawyer Beatriz Duro said.
UrbaGestion, the fund that owns Ms Abascal's apartment, offered her a preliminary agreement on Monday that would allow her to return home if she agrees to its terms.
"She should never have been forced to leave," Ms Duro told reporters. "I hope this case serves to provide a collective response to the housing crisis."
Ms Duro also criticised UrbaGestion for refusing, until recently, to negotiate or hold talks.
So much so, there are now multiple reports that the UAE - which includes the emirates of Dubai and Abu Dhabi - has suggested that major investments in UK projects could be in jeopardy should Man City be punished.
Prime Minister Andy Burnham said he would be "really concerned" to see the owners sell up, before No 10 later said in a statement that no team is "above the rules".
Emirati officials quoted by Bloomberg said "the Premier League's actions" would "have an influence on the bilateral state relationship".
That could jeopardise billions of pounds of private investment for a hi-tech Silicon Valley-style hub between Oxford and Cambridge.
The crisis blew up after City were found guilty of "serious breaches" of financial rules by Premier League appointed independent commission. The club is appealing against the findings, saying it has "irrefutable evidence" to prove its innocence.
The club was taken over by an Emirati royal, Sheikh Mansour bin Zayed Al Nahyan, who is deputy prime minister of the UAE, in 2008 for £150m. His half-brother, Mohamed bin Zayed Al Nahyan, is president.
One of the key people facing scrutiny is chairman Khaldoon Al Mubarak - who met business secretary Jonathan Reynolds at No 10 two weeks before the Premier League announced its decision.
Who is Khaldoon Al Mubarak?
Khaldoon Al Mubarak is one of the Middle East's most prominent business leaders. The 50-year-old is also an influential UAE government policymaker, and an international envoy.
He is married to wellness studio owner Nadia Sehweil. The couple met in high school and have a family together, according to Abu Dhabi-based news outlet The National.
Al Mubarak's father, Khalifa Al Mubarak, was a diplomat who served as the UAE's ambassador to France.
He was assassinated in Paris in February 1984, shot on a street outside his home close to the Eiffel Tower.
The killing was linked to the Abu Nidal Organization, a violent group calling for Israel's destruction.
Mr Mubarak sat with Donald Trump in Davos this year, signing on his Board of Peace on behalf of the UAE government.
Before entering European football, Mr Mubarak was a key liaison with F1 when the Abu Dhabi Grand Prix joined the circuit.
Since 2008, he has been the chairman of Manchester City Football Club, the most successful Premier League club of the past decade.
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Mr Khaldoon is also the chairman of City Football Group, established in 2013 to be an investor and operator of international football-related businesses, including Manchester City FC, New York City FC, and Melbourne City FC.
The group, valued at more than US$6bn (£4.53bn), now has 13 clubs within its global network.
He is the managing director and group CEO of Mubadala, a $330bn (£249.18bn) sovereign investment firm headquartered in Abu Dhabi, with assets in more than 50 nations across six international offices.
He has headed the company since it started in 2002 and overseen financial returns for Mubadala's shareholder, the government of Abu Dhabi.
Mr Khaldoon also chairs the Board of Abu Dhabi Commercial Bank and is vice chairman of investment company MGX.
He is on the board of Abu Dhabi National Oil Company (ADNOC), L'IMAD Holding Company, and G42, the Abu Dhabi-headquartered global AI company.
He is also a member of JP Morgan's International Council.
Mr Khaldoon holds the mandate of Chairman of the Executive Affairs Authority, the government agency that provides strategic policy advice to His Highness Sheikh Mohamed bin Zayed Al Nahyan, president of the UAE.
He is also the presidential special envoy to China and leads several country files on behalf of the UAE.
In January 2024, he became a founding member of the Artificial Intelligence and Advanced Technology Council (AIATC), of which he was appointed secretary general.
Mr Khaldoon played a key role in establishing New York University Abu Dhabi and serves on the New York University Board of Trustees.
In 2013, Mr Khaldoon was made a Commander of the Order of the British Empire (CBE).
He has a degree in economics and finance from Tufts University in Boston, US.
The plane, used as an air ambulance, had four crew members and two passengers on board when it left the British overseas territory for an overnight flight to Massachusetts.
A search is underway off the coast of the island of Nantucket after the Gulfstream G100, registered to Latitude Air Ambulance, lost contact with air traffic controllers in the early hours of Saturday morning.
"The US Coast Guard Northeast District is searching Saturday for a missing medical transport aircraft with six people aboard after the aircraft lost contact while traveling from Bermuda to Boston," the Coast Guard said in a statement.
"Coast Guard air and surface crews are searching an area off the coast of Nantucket."
The search for the jet includes crews in the air and on the water, the coastguard added.
Steven MacKinnon, Canada's minister of transport, said on X that four Canadians were on board the aircraft.
"My thoughts are with everyone on board, as well as their families, loved ones and colleagues during this incredibly difficult time," he said.
"We are closely monitoring the situation, and are working with the relevant authorities as search and rescue efforts continue. I want to thank all first responders involved for their ongoing efforts."
In a statement posted on Instagram, Bermuda Premier David Burt said: "We are praying that all six people will be found safe."
According to data from flight tracking website FlightAware, the jet was flying at around 24,000ft (7,315m) for much of the flight before descending 13,000ft (3,962m) in about two minutes shortly before flight controllers lost contact.
Local TV station Boston 25 posted an audio clip in which an air traffic controller can be heard asking the Gulfstream pilot: "You said you're coming in blind? Is that what you said?"
The controller then asked whether the plane was declaring an emergency. No response was heard.
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Clarence Togeretz, the director of flight operations at Ontario-based Latitude Air Ambulance, said that the aircraft was was carrying out a medical evacuation in Bermuda.
"We always get rather concerned when our crew doesn't report to us in a timely manner," Mr Togeretz told NBC News, Sky's US partner network.
"But I will say that again, optimistically and positively, that doesn't mean that the worst has happened."
A spokesperson for the Massachusetts Port Authority, which operates Boston Logan International Airport, said: "Our thoughts are with those on board and their loved ones as the search continues."