Keane started his football with South Dublin schoolboy side, Crumlin United F.C. where his talent was recognised at an early age. As an U-10 schoolboy he was paid 50p a goal, and was soon being watched by scouts from a number of English professional clubs, including Premier League side Liverpool F.C..

However, he turned down Liverpool to join Wolverhampton Wanderers F.C., reasoning that he had a greater chance of breaking into the first team at the First Division side. He made his first professional appearance in 1997, and played at Molineux for two seasons, making 88 appearances and scoring 29 goals, before a �6m transfer to Coventry City F.C. in 1999, a then British record for a teenager.

After a successful season at Coventry, where he scored 12 goals in 34 games, he had become one of the hottest properties in English football, and was being courted by many of the biggest clubs in football.

In the end, he was signed by Marcello Lippi of Internazionale for �13m, where he teamed up with the likes of Ronaldo, Christian Vieri and Alvaro Recoba.

However his dream move to Italy soured when Lippi was sacked soon after Keane arrived, and Lippi's successor, Marco Tardelli deemed Keane surplus to requirements. Keane's ambition refused to let him stagnate in Italy, and, in December 2000, he was loaned out to Leeds United F.C..

His Leeds career got off to a cracking start, scoring 9 goals in 14 starts before the Leeds manager, David O'Leary, made his loan deal permanent in May 2001 at a cost of �12m. The following season was not so bright, and he found himself dropping down the pecking order. His form suffered and he only managed 10 goals in 36 appearances. Meanwhile, Leeds's financial troubles were forcing the club to sell many of its players, and Keane joined the exodus when he was sold to Tottenham Hotspur F.C. just before the 2002/2003 transfer deadline for a fee of �7m.

Upon signing for Tottenham, the Spurs manager Glenn Hoddle said Keane was ideally suited to Tottenham and could make White Hart Lane his "spiritual home" for years to come. He repaid this faith with some outstanding displays, earning the club's Player of the Year awards in his first two seasons at Tottenham. He bagged 13 and 16 goals respectively in those first two seasons for Spurs.

His third season, 2004/2005, was more frustrating. Despite finishing with his highest return of goals in a season for Tottenham, 17, he played second-fiddle to Jermaine Defoe for much of the season. The frustration culminated in Keane storming from the dugout towards the end of a game against Birmingham City in April 2005 after all the substitutes had been used, meaning he would not get a chance to appear. He was fined �10,000 and forced to train with the reserves after the outburst and his future at the club was thrown into doubt. Article

He knuckled down after this incident but the 2005/2006 season started as the previous one had ended, with Defoe being preferred to partner Mido in Tottenham's strikeforce. However, Defoe's strikerate continued to disappoint and Keane's persistence paid off in November when manager Martin Jol eventually gave Keane a chance to replace Defoe and stake his claim.

He grabbed the chance with both hands, started playing some of the best football of his career and by March had overtaken Mido as the top goalscorer at the club, with 14 goals as at April 1, 2006. He had also been made the stand-in captain, taking the captaincy on those occasions when Ledley King was not available.

He is a firm fans favourite, and is regarded as a great professional. Hoddle once said of Keane's personality, "He's such a bubbly lad that anyone who meets him loves him, he is great for team spirit".

Edgar Davids and Keane were involved in a training ground fight in December 2005, but since then the pair have publicly made up and can be seen encouraging each other on the pitch. Davids has claimed that this incident has inspired Tottenham into a new togetherness, firing their push for European qualification.

In February 2006, Inter's owner and president, Massimo Moratti, admitted his regret at letting Keane go some five years earlier, saying Keane was now playing "perfect" football. Article

On the March 3, 2006, it was publicly released that Keane had signed a new four year contract, keeping him at the club until 2010.

Keane was one of ten Spurs squad members to be struck down by norovirus, a form of viral gastroenteritis, on the evening of 6 May 2006 before their crucial final game of the season against West Ham United. A win would have seen Spurs qualify for the Champions League for the first time ever, ahead of arch-rivals Arsenal. However, several players woke up the next morning feeling ill and Spurs tried to get the game postponed. They countered that the players needed extra time to get fluids and some food on board as they had not been able to eat until then. Due to a number of factors, a suitable time could not be agreed to reschedule the game. Additionally, the Premier League were not willing to rule out punishment if the game did not go ahead, so Spurs turned down the option of a minimal postponement of two hours and played the game on time with several key players clearly not match fit. Spurs went on to lose the game and surrendered 4th position in the league and a Champions League place to Arsenal. Conspiracy theories abound, but manager Martin Jol did not think dirty tricks had been going on.