The 23-year-old centre has signed a three-year deal.
The son of former Castleford legend Lee, Crooks is yet to play first-grade for the Eels, after joining them at the beginning of the current campaign.
But he could have been getting ready to wear black and white again, the player revealed.
“Joining Parramatta Eels was designed to improve my skills and mature me both as a player and a person in the highest quality environment in world rugby league, while experiencing a new independent and memorable lifestyle,” said Crooks.
“Even though I have not yet managed to break through and play in the NRL, I believe I have achieved my goals in my career development and will return to Super League a better player for the experience.
“I have loved by time at Parramatta and thank everyone for their guidance and support.
“We have had talks with a handful of Super League clubs, including a return to Hull FC. Castleford Tigers are my hometown club who made a determined effort to sign me both now and when I first turned professional, and I am anticipating an exciting new chapter in my career,
“The Tigers have made massive strides on and off the field in the past two years and I am looking forward to working with Daryl Powell, who has a proven track record of bringing out the best in players and thus fulfilling their potential.”
Tigers coach Daryl Powell is delighted that Crooks will be at Cas next season.
“I am really pleased we have been able to secure the signature of Ben Crooks at the Tigers,” he said.
“He has shown huge potential as a player and we are confident that our environment will bring the best out of him in every facet of the game.
“Ben is quick and athletic with a great try scoring ability who we feel will fit neatly into the way we like to play the game.”