Redknapp, heavily linked to the England job before the Football Association appointed Roy Hodgson last month, had one-year remaining on his contract and said in recent weeks he hoped to renew it.
But after a rollercoaster season where Spurs narrowly missed out on a place in the Champions League after pushing for the title, and Redknapp was cleared of tax evasion by an English court, chairman Daniel Levy decided a change was necessary.
"This is not a decision the board and I have taken lightly," Levy told the club's website in the early hours of the morning.
"Harry arrived at the club at a time when his experience and approach was exactly what was needed.
"This decision in no way detracts from the excellent work Harry has done during his time with the club and I should like to thank him for his achievements and contribution."
SAD TO GO
Redknapp said the club had simply wanted a change and qualifying for the Champions League would not have changed that.
"We finished fourth and were unlucky at the end," he told Sky Sports television before heading off for a round of golf. "But I think the same outcome would have happened.
"I had four great years at Spurs. All you can do is leave the club in a better state than you found it and I did that, for sure."
The 65-year-old said he would look for another job in soccer, declared himself "fit as a fiddle" and would not be sitting around moping.
Redknapp added the England speculation and contract negotiations were not the reasons for his departure.
He was appointed manager in October 2008 after Juande Ramos was sacked with the club bottom of the league with two points from eight matches.
Former West Ham United, Southampton and Portsmouth manager Redknapp resurrected their fortunes and took them to the League Cup final that season where they were beaten by Manchester United on penalties.
Further success came the following year when he led them to the Champions League for the first time after a fourth-place Premier League finish and collected the manager of the year award.
An unlikely run in Europe's top competition saw Spurs eventually knocked out in the quarter-finals by nine-times champions Real Madrid but only after they had turned heads by beating multiple winners AC and Inter Milan.
CANNOT SPELL
Redknapp was hugely popular with Spurs fans and tested their allegiance by signing Emmanuel Adebayor and William Gallas, who both played for arch-rivals Arsenal, but the manager was proved right as the supporters were won over by their strong displays.
His admission during his tax evasion case in January and February that he was "the most disorganised person in the world" and that he writes "like a two-year-old and can't spell" was hardly the confession an owner of a high-flying, big-spending club wanted to hear from their manager.
During the trial Tottenham's good form continued but once Redknapp was cleared, and Fabio Capello stepped down as England manager and a massive media-led campaign was launched for the Spurs man to replace the Italian, problems started.
A 5-2 humbling at Arsenal in February was the start of three consecutive league defeats and although Spurs rallied to finish in the fourth and last qualifying slot, they were denied a Champions League position because sixth-placed Chelsea beat Bayern Munich in the final to win the trophy.
With no Champions League football next season and acknowledging last week that he would have taken the England job if it had been offered to him, media speculation grew that Redknapp was set to depart, makin
