Few players embodied attacking football quite like Keegan. Fewer still returned to a club they adored and transformed its fortunes as dramatically as he did at Newcastle United.
A Ballon d'Or winner, European Cup winner with Liverpool, Bundesliga champion with Hamburg and England captain, Keegan's playing career placed him among the greatest footballers of his generation. Yet on Tyneside, it is perhaps his work as manager that secured his place in Newcastle folklore forever.
When Keegan walked back through the doors of St James' Park in January 1992, Newcastle were staring into the abyss. The club sat in the old Second Division relegation zone, finances were stretched and supporters feared an unthinkable slide into English football's third tier.
Within months, survival had been secured. The following season Newcastle won the First Division title, earning promotion to the inaugural Premier League before going on to become one of England's most exhilarating teams.
Former Newcastle midfielder Liam O'Brien witnessed that transformation first-hand.
Speaking exclusively to Football Presse, the Republic of Ireland international recalled that even those inside the dressing room questioned whether Keegan's appointment would work.
"It was a massive gamble for him, it was a massive gamble for the club because he hadn't managed," O'Brien said. "We were, as a team, as players, saying, 'Well, he hasn't managed, he's been in Spain for the last 10 years in Marbella.'
"So that's what I'm saying, his reputation was on the line. It was a gamble for him to take the job, it was a gamble for the club to employ him."
Those doubts disappeared almost immediately.
O'Brien says Keegan's greatest strength wasn't tactical innovation as much as the personality he brought into every room he entered.
"It was actually a masterstroke," he said. "He came in, he had this... he was very charismatic, he had this aura about him, he was full of enthusiasm, great personality, and the players really loved him.
"And he just loved Newcastle United.
"He loved the fans because they treated him so well when he was there as a player.
"He just said, 'These fans do not deserve this club to be where it is. I'm going to do my best to get them out of this.'"
That connection between Keegan and the city was unique.
After dazzling supporters as a player between 1982 and 1984, he returned eight years later carrying not just enormous expectation but genuine emotional investment in restoring Newcastle's status. For O'Brien, that passion spread quickly through the squad.
"We stayed in the division that season," he recalled. "And the following season we went on to win the division to get back into the Premier League.
"That was an unbelievable turnaround in 14 or 15 months."
The rebuilding did not happen overnight.
O'Brien remembers Keegan relentlessly strengthening the squad, adding experience and quality piece by piece until Newcastle became promotion favourites.
"He brought in John Beresford and Paul Bracewell and Barry Venison, and they were excellent," he said. "So he kept chipping away, and then he got in Rob Lee, who was really, really good for us, and then Scott Sellars, and then Andy Cole at the end of the season.
"You could see that we were going to do so well.
"You could just sense that the club was going back in the right direction."
While Keegan would later become synonymous with Newcastle's fearless attacking football during the "Entertainers" era, O'Brien says there was also a practical side to his management.
Compared to predecessor Osvaldo Ardiles, Keegan made Newcastle more balanced without abandoning their attacking identity.
"It was more like a 4-4-2, so a bit more solid," O'Brien explained. "But they still had the same principles.
"They still wanted to go out and entertain the fans and play well, play to your strengths and enjoy the game."
That philosophy would later produce one of English football's most memorable teams, featuring David Ginola, Les Ferdinand, Peter Beardsley, Rob Lee and eventually Alan Shearer, with Newcastle coming agonisingly close to winning the Premier League in 1995-96.
Although the title ultimately eluded him, Keegan restored Newcastle to the elite and re-established the club as one of England's biggest attractions.
O'Brien also experienced Keegan's personal side. After leaving Manchester United, the midfielder later found himself needing match fitness while serving a suspension early in one season.
Keegan immediately supported him.
"I asked Kevin Keegan could I go over (to Ireland) because I was suspended for the first three games of the new season," O'Brien recalled.
"He said, 'Yeah, go and get your fitness.'"
It was a small gesture, but one that reflected the trust players felt under him. More than three decades later, O'Brien still speaks with warmth and admiration about the man who revived Newcastle's fortunes.
His memories echo those of countless players and supporters who experienced Keegan's infectious belief that football should be played with courage, ambition and a smile.
For Newcastle United, Kevin Keegan was far more than a legendary player or successful manager.
He gave a sleeping giant its belief back.
And for those fortunate enough to play under him, like Liam O'Brien, that legacy will never fade.