The 35-year-old Irishman was speaking to the Galaxy’s official website on Wednesday following confirmation that the MLS club had clinched the much-anticipated signing of Dos Santos from Spanish side Villarreal for around $7 million [£4.5 million].
Keane is more than familiar with the Mexico international, having been teammates with him at Tottenham between 2009 and 2011 after returning to White Hart Lane from a brief six-month stint at Liverpool.
With Dos Santos struggling to adapt to life in England following his move from Barcelona in June 2008, the experienced striker even took a special interest in mentoring his fellow attacker, making an effort to give him tips in training and help him with the language.
His efforts proved in vain in the end, however, as the skilful prospect would manage just three goals in 31 total appearances for the club over the next four seasons, while taking in loan spells at Ipswich Town, Galatasaray and Racing Santander, respectively.
Nevertheless, he has managed to showcase some of his undoubted potential back in La Liga since leaving Spurs for Real Mallorca in August 2012, and Keane believes the 90-times capped forward will prove a nightmare for MLS defenders to deal with.
Speaking on their relationship from their time at Tottenham, Keane said: “He’s a great guy. He was a young kid when he came to Tottenham … but every time that he trained you could see what a player that he was, and a good kid in the dressing room. I’m very excited to have him here.
“We had a good relationship when he came to Tottenham. He came to Tottenham as a young kid who couldn’t’ speak English so I made sure that he was looked after.
“I looked after him when he came over, and we’d stayed in contact since. He’s here to win. He wants to make sure that he takes the Galaxy to the next level.”
LA’s deal for Dos Santos comes following a long-running pursuit of the former Barca hotshot which dates back to 2011, before the MLS Cup holders began negotiations with his agent in recent weeks after Villarreal declared their intentions to cash in on his signature.
The club already had all three Designated Player spots filled by skipper Keane, Omar Gonzalez and fellow summer signing Gerrard, respectively, at the time but used the recently-introduced “Targeted Allocation Money” to buy down Gonzalez’s contract and open up another slot.
Their new big-name addition had an underwhelming 2014-15 season with Villarreal, recording three assists and just one goal in 26 La Liga appearances, but he managed to score 11 times for the club during the previous league campaign.
Aged 26, he is now entering the prime of his career and, as one of the stars of the Mexico national team, should prove a major hit among the Latino population of Southern California.
Keane, though, is more concerned with his impact on the pitch and believes the El Tri favourite has come on in leaps and bounds since his forgettable spell in north London.
“He’s matured a lot as a player. I’ve been watching a lot of his games," he added to lagalaxy.com. "Last year, he was one of the best players in La Liga, he’s certainly matured. He’s at an age where he’s coming into his peak. He’s got everything, he can do everything. He’s matured as a person; he’s not coming here to be living in LA. He’s coming here because he wants to win.
“He can play left, he can play right, he can play up front and he can play as a number 10. He’s very skillful, and he’s basically got it all. I’m delighted that he’s got it all.
“I think that he’s going to be a superstar in this league. There’s no question about it. He has the right mentality, he has the flair, and I’m sure that Galaxy fans are going to be excited to see him play.”
With Galaxy head coach Bruce Arena now having Keane, Gerrard and Dos Santos at his disposal, as well as US international Gyasi Zardes and former West Ham United midfielder Sebastian Lletget, the club are certainly not lacking firepower in their bid for a fourth MLS Cup title in five seasons.