The Sky Blues have promoted their National Youth League coach to the top job, with the former Norwich City star filling the role left by the departed Vitezslav Lavicka
Sydney turned to former Norwich City midfielder Crook after moves for Central Coast Mariners coach Graham Arnold, Newcastle Jets counterpart Gary van Egmond and Crystal Palace assistant Tony Popovic came to nothing.
Popovic, having rejected his former club, is now free to join the A-League's new western Sydney team if he so wishes.
Crook had a superb club career in England with Tottenham and Norwich, picking up three England B caps before eventually retiring after a stint with the Northern Spirit in the National Soccer League.
The 49-year-old has held an array of coaching roles since his playing career ended, holding assistant jobs at J.League club Avispa Fukuoka, Norwich and Australia's Under-20 side since his sole top-flight head coaching post at the Newcastle Jets ended in 2004.
"I'm thrilled and honoured to be named as head coach of Sydney FC," said Crook, who coached the Sky Blues' National Youth League side for the past two campaigns.
"This club is very special to me after being part of its birth and early success and since returning to Australia I have enjoyed working with the younger players.
"Over the last few months the competitive urge has been re-ignited inside me and after spending the last two seasons nurturing and developing young players the time is right for me to step back into a head coach role.
"To get this opportunity at Sydney FC is fantastic and I can't wait to start working on the pitch with the players, [coaches] Steve Corica, Zeljko Kalac and the football staff to make sure we get Sydney FC back where it belongs.“We have a lot to do but I’m excited about working with Gary Cole [football director] on our recruitment and retention to bring success to the club and a team that the Sydney FC fans can be proud of."
Former Sydney FC marquee star Dwight Yorke believes Crook - despite not being the club's first-choice candidate - was a good fit for the role.
"He's a fantastic guy, he knows the football game and has huge experience in the English Premier League and around the world," said Yorke, who was briefly linked with the role and worked with the new coach when Crook was an assistant under Pierre Littbarski for the A-League's debut season in 2005-06.
"When I was playing for Sydney FC, Crooky was always there to help me when I needed advice. He knows people’s strengths and weaknesses and he always got the best out of me.
"I have no doubt he will be a huge success and we'll see a massive improvement in Sydney FC next season. With the players he has, I think they will either win or go very close to winning the A-League."