Although Keane had proved himself as a reliable goalscorer for the likes of Wolverhampton Wanderers, Leeds United and Spurs before the move, Fernando Torres was very much the main man at Anfield.
© Getty Images
That did not deter Keane from making the switch, with the Irishman revealing that he had always been a Liverpool fan and was delighted to have joined his boyhood team.
Things didn't quite go to plan at Anfield, however, and after a spell of seven goals in 28 appearances amid a genuine title charge from Liverpool, Keane was back at White Hart Lane.
A little over six months after leaving Spurs, he rejoined the North London side five years ago today for the reduced fee of £12m, rising to £16m with add-ons.
Despite the fee being significantly less than Liverpool had originally bought him for, Keane became the most expensive player ever to be sold by the Merseyside club up until then.
"It was a difficult decision to leave Tottenham in the first place and it turned out it was not the right move for me," Keane admitted at the time.
"Some Tottenham fans may feel I let them down but I will give this club my all. The club has terrific fans and I want to repay them for all their support. We have got to get on and fight our way up the table."
Spurs manager Harry Redknapp was also delighted to have the experienced striker back and said: "I'm very pleased to have signed him, he's just the type of player we need – his enthusiasm and work-rate – and he's a terrific character to have around the place."
The 28-year-old made his second debut for the club in a rare goalless derby against local rivals Arsenal before reopening his account on March 4, hitting the first goal in a 4-0 win over Middlesbrough.
Three days later he scored a vital late equaliser for Spurs against Sunderland and went on to find the net five times in 14 games over the remainder of the season.
On the final day of the campaign he made a return to Anfield and, despite his brief stint at the club, was given a warm reception by the home fans as he scored in a 3-1 defeat for Spurs.