The deal will cover all four years of arbitration for Castro, plus his first three years of free agency. The contract includes a $6 million signing bonus, with salaries of $5 million for 2013 and '14, $6 million in '15, $7 million in '16, $9 million in '17, $10 million in '18 and $11 million in '19. There is also reportedly a club option for '20 at $16 million, or a $1 million buyout.
If Castro wins the Most Valuable Player Award or has two top-five finishes, the final year of the deal and the option year would each escalate by $2 million.
"My family has changed, but I'm not going to change myself," Castro said. "I'm going to work hard every day on the field. I'm going to be here for a long time, and will work hard every day and be humble and stay like that for all of my career."
At a minimum, the contract lasts through Castro's 20s, as he will not turn 30 until after completing the seventh season of this deal.
"I think Castro is one of the young players who come around once in a while, and they can be as good as they want to be," Cubs manager Dale Sveum said of the young infielder.
"The ceiling is very high, but it's still up to those individuals to make a difference on an everyday basis -- and not just as a hitter, but as a player and a winning hitter, and always making a difference in a ballgame to win ballgames."
Castro and prospects Jorge Soler and Gerardo Concepcion are the only Cubs players under contract beyond 2014. Soler signed a nine-year, $30 million deal that runs through 2020, and Concepcion agreed to a five-year, $6 million contract through 2016.
"We looked at it and said to ourselves we wanted to have Starlin in his prime," Hoyer said. "Continuity is an underrated thing in sports. If you can make sure you have the same building blocks year after year, it's really important, and with him it was obvious.
"I think people sometimes forget when they talk about Starlin, they forget about his age," Hoyer said. "You have all the prospect lists all over the place, and this guy is younger than those top prospects and he has 500 hits. I think it's important to remember and put his age into context. We're talking about a guy who would've been in his first year of pro ball if he had gone to college in the states."
Castro has been with the Cubs longer than Hoyer, originally signing with the team in October 2006. But Hoyer and Theo Epstein, Cubs president of baseball operations, were impressed by the shortstop's work habits.
"His talent got him here at a young age," Hoyer said. "He's still learning in the big leagues. He's showed he'll put in the work to be a great player. I have no question there will be a lot of special Starlin Castro moments here as a Cub."
A two-time National League All-Star, Castro leads the NL with 486 hits since making his Major League debut on May 7, 2010, at the age of 20. Last season, he was the youngest player to lead the NL in hits with 207.
Entering Tuesday, Castro was batting .276 with 12 home runs, 18 doubles, nine triples and 63 RBIs on the season. However, he also leads all Major League shortstops with 21 errors, two of which came on Monday night.
Hoyer and Castro's agent, Paul Kinzer, began discussions about a long-term deal in July, and were worried it might become a distraction. Was it?
"A little bit," Castro said. "That's why I told my agent, 'When you are close, let me know.' I wanted to take pressure off myself."
Veteran Alfonso Soriano has been Castro's other mentor besides his father. In the shortstop's first season in 2010, Soriano took Castro into his home.
"In this game, he's the most important guy for me," Castro said. "This guy, he took me to live with him in his house, and every time talked to me about baseball, about how important baseball is for you and your family. You only know how to play baseball. He's one of the guys I say thank you to for helping me in this game."
Castro's father was a fisherman, and there were days when it was difficult for the family. Castro is one of five children, and now he, his two brothers, two sisters and their parents are set for life. After the announcement at Wrigley Field, Castro hugged his father.
"He got me here," Starlin said.
This is a life-changing contract.
"To be 22 years old and get that kind of money is a lot to handle sometimes," Sveum said. "I think, for the most part, when you get that first contract you can relax and understand there's really only one thing to play for, and that's winning the World Series."
That's next on Castro's wish list.
"That's what I'm looking for," Castro said. "That's the only thing that's important now, is to win a World Series here."