In February 1996, McCarthy was handed the apparently impossible task of stepping into the giant shoes of Jack Charlton as the Republic of Ireland manager. A less courageous man may well have turned down what many observers felt was a nigh-on impossible task.
If the towering McCarthy had proved he had courage in abundance during his playing career, he needed to be just as courageous in order to meet the challenge of managing the Irish squad.
Many observers would agree that Mick reacted well to the challenge of following Big Jack, although he lacked a little Irish luck in many crucial games.
Mick’s long journey to the world stage began in Yorkshire. Born in Barnsley of Irish parents, he made his debut for his hometown club as an 18-year-old in 1977 and became a stalwart of the defence in the Tykes team that won promotion from the old Fourth division to the Second.
He moved on to Manchester City in 1983 for £200,000 and won his first Eire cap a year later. In 1985, his contribution as a rugged stopper in City's defence helped them return to the top flight.
Mick later left City for Celtic and helped the Bhoys to the Scottish League and Cup double in 1988. But after just 48 appearances at Celtic Park, he was transferred to France for a brief spell with Lyon.
By March of 1990 Mick was back in England, initially on loan with Millwall until a £500,000 fee made his deal permanent with the south London club.
The same summer saw the Republic at the World Cup Finals for the first time in their history and Mick played in every game of the remarkable odyssey that carried them to the last eight, where they finally succumbed to the hosts, Italy, in Rome.
In March 1991, at the age of 32, Mick became Millwall's player-manager, making his final appearance as player two months later against Southend.
He was active as an international player for another year though, and won the last of his 57 caps in May 1992 in Ireland's 2–0 win over Portugal in Boston.
He was then free to concentrate on management and having steered Millwall to third in the First Division in 1994, narrowly missed out on promotion as his team went down 2–0 to Derby County over two games in the semi-finals.
Millwall responded as Mick demanded the following season however, if only in the cups, beating both Arsenal and Chelsea in the FA Cup, before bowing out to QPR, whilst reaching the fifth round of the Coca-Cola Cup.
Indeed with their cup heroics out of the way the Lions recaptured their form in the league recovering from a poor start to finish 12th.
The following season was something of a mirror image as Mick's side topped the table, before slumping to mid-table, which was when the offer came from the FAI to follow succeed Jack Charlton.
Mick was appointed Ireland's manager on February 5th 1996, two days before his 36th birthday, with the task of reviving the fortunes of an ageing side who had for a decade proved that the team was much, much greater than the sum of it's parts.
November 1997 saw Eire in a head to play off with Belgium for a place at France 1998, but they were beaten 3–2.
In the Euro 2000 qualifying groups Mick's young side were paired with both Yugoslavia and World Cup semi-finalists Croatia, but they seemed set to upset the odds as they topped the group. However, cruel injury-time goals in Croatia and then Macedonia condemned them once again to the play-offs where they lost out to an impressive Turkish side over two legs.
The qualifiers for the 2002 World Cup again saw the Irish suffer a certain degree of misfortune as they surrendered a two-goal lead in Holland to a world class Dutch side that managed to level the game at 2-2. Another away draw in Portugal followed, before a 2-0 home win over Estonia put the Irish in a reasonably strong position to qualify.
With Holland, Portugal and Ireland all fighting for the top two positions in the table, Mick's men gained a huge advantage with a 1-0 over the Dutch at Landsdowne Road, courtesy of a well-taken goal from Jason McAteer.
It effectively secured second place in the group for the Irish, who lost out on top spot on goal difference to Portugal. That meant another chance to qualify for a major finals via the play-offs, this time against Iran.
It was third time lucky for Mick and his men, who booked their place in the World Cup finals with a 2-1 aggregate win over the Iranians.
Mick had been awarded an extension to his initial contract in October 1999 that saw him through to the end of the 2002 World Cup qualifying campaign. Having achieved his aim of taking the team to the tournament in Japan and South Korea, Mick signed another new deal which was set to keep him in charge until after Euro 2004.
The World Cup finals themselves turned out to be the most dramatic period of Mick's tenure as Ireland boss.
As the team headed out to the Far East with spirits and expectations high, the country looked to the manager, and captain Roy Keane, to continue their impressive form.
However, after admitting he had nearly walked out on the squad in the run-up to the World Cup, Keane publicly criticised the team's training facilities and general attitude.
During what were supposed to be 'clear-the-air' talks with his manager, the Manchester midfielder ended up rowing with the manager and insulting him in front of the rest of the squad, and was subsequently sent home.
Despite the loss of his captain, Mick led his team through to the second round of the World Cup, with draws against Cameroon and Germany, and victory over Saudi Arabia.
In the last 16, Ireland came up against one the World Cup favourites, Spain, and went out on penalties after a 1-1 draw and a dramatic half hour of extra time.
It was certainly the zenith of Mick's reign as Ireland boss, coming so soon after the most difficult period he had endured.
He further enhanced his reputation when he joined the BBC's panel of pundits for the remainder of the tournament and added his own Yorkshire wit to their coverage.
As the fall-out from the Keane saga continued, with the release of both Keane and McCarthy's latest books, Mick focussed returned to matters on the pitch with the Euro 2004 qualifiers.
His team made a disastrous start, losing their first two games to Russia and Switzerland, leaving them with a mountain to climb to qualify for the tournament in Portugal.
Despite receiving the backing of the FAI during the summer, the pressure on Mick grew, and he resigned his post on November 5 2002 having agreed a compensation package with the Irish board.
His impact on the Irish side was phenomenal however, lifting them from 54th to 13th in FIFA's world rankings in just over five years.
Mick's reputation and international experience meant he was always likely to be given a chance to fulfil his desire of managing in the top flight, and that chance came at Sunderland.
Having intially been considered for the post following Peter Reid's dismissal in October 2002, Mick was appointed to succeed Howard Wilkinson five months later and faced the seemingly impossible task of keeping the club in the Barclaycard Premiersihp.
With nine games of the season remaining, the Wearsiders were seven points adrift of safety at the bottom of the table, and although Mick vowed to give his all to keep them up, his appointment was more for the long-term than a simple quick-fix.