Steve Bruce has left his position as Newcastle manager by "mutual consent", 13 days after a Saudi-led takeover at St James' Park, the Premier League club announced on Wednesday.
Bruce, whose departure was widely expected, took charge of his 1,000th match as a manager in Sunday's 3-2 defeat by Tottenham -- his only game under the new owners.
His assistant, Graeme Jones, will take charge of the team for Saturday's trip to Crystal Palace, with the Magpies still searching for their first Premier League win of the season and sitting just one place off the foot of the table.
Former Roma coach Paulo Fonseca is the bookmakers' favourite to succeed Bruce, with ex-Bournemouth boss Eddie Howe and former Borussia Dortmund manager Lucien Favre also linked with the job.
"Newcastle United can confirm that Steve Bruce has left his position as head coach by mutual consent," said a club statement, which confirmed the search for a new head coach was under way.
"He leaves the Magpies after more than two years in charge, having steered the club to 13th and 12th-place finishes in the Premier League."
Bruce, 60, said he was grateful to have had the opportunity to manage the "unique" club, saying he had experienced "highs and lows" during his tenure.
"This is a club with incredible support, and I hope the new owners can take it forward to where we all want it to be," he said. "I wish everyone the very best of luck for the rest of this season and beyond."
In an interview with the Daily Telegraph, Bruce admitted the Newcastle job could be his last.
"It's taken its toll on my whole family because they are all Geordies (from the Newcastle area) and I can't ignore that," he said.
"This will probably be me done as a manager -- until I get a phone call from a chairman somewhere asking if I can give them a hand," he added. "Never say never, I've learnt that."
Bruce, who managed a long list of clubs including Sunderland and Aston Villa, also hit out at the critics whom he felt never gave him a chance at the club.
"By the time I got to Newcastle, I thought I could handle everything thrown at me but it has been very, very tough," he said.
"To never really be wanted, to feel that people wanted me to fail, to read people constantly saying I would fail, that I was useless, a fat waste of space, a stupid, tactically inept cabbage head or whatever. And it was from day one."
- Newcastle takeover -
The £305 million ($420 million) Newcastle takeover was rubber-stamped by the Premier League earlier this month after it received legally binding assurances that the Saudi state would not control the club.
That was despite the fact that Saudi Arabia's state sovereign wealth fund -- the Public Investment Fund -- owns 80 percent of the club and Crown Prince Mohammed bin Salman is listed as the PIF board's chairman.
The protracted takeover, which ended the 14-year reign of the unpopular Mike Ashley, has been criticised by human rights groups as a Saudi attempt at "sportswashing" its reputation on the international stage.
Bruce was a deeply unpopular figure with the Newcastle supporters, in part due to his past as manager of northeast rivals Sunderland.
A recent poll from the Newcastle United Supporters Trust found that 94 percent of fans wanted him to quit.
However, he kept the club afloat by staying out of relegation trouble in his two full seasons in charge despite the limited resources provided by Ashley.
A wave of Saudi investment is expected to transform Newcastle's fortunes on the pitch, following the example set by English champions Manchester City and French powerhouse Paris Saint-Germain.
The club have not won a major trophy since 1969 despite regularly attracting crowds of more than 50,000.