The 31-year-old striker gradually fell down the pecking order at Harry Redknapp's club, but his experience may prove vital in Major League Soccer
Throughout his 14-year (senior) career, Keane has been contracted to nine clubs, including Liverpool, Inter Milan and Celtic.
: "I have always wanted to come and play in MLS so it's the perfect combination for me and a dream come true.
"My family and I have already been made to feel very welcome in telephone calls from (president of Galaxy owners AEG) Tim Leiweke and (head coach) Bruce Arena.
"Also when David Beckham came and trained at Spurs recently he couldn't speak highly enough about the Galaxy, their fans and the league in general, so I can't wait to get over and get started.
"I have already discussed football with Bruce Arena and I know exactly what he wants from me. I am fit, fresh and ready to go. I've come here to score goals and help this team achieve their goals.
"This is a massive opportunity for me in my career. I aim to grab it with both hands and hopefully help give the Galaxy fans what they want."
Having scored 51 goals for the Republic of Ireland, Keane
recently overtook England and Manchester United legend Booby Chartlon, as he became the leading international goalscorer from the British Isles.
It has also been reported that David Beckham
played a big part in the transfer.