The event was attended by hundreds of students from around the city.
"Baseball gives them friendship," Castellanos said. "I've made countless friends all over the country playing this game. It's teaching life lessons that you can take not only on the field, but off the field: teamwork and being competitive."
UAW-Ford donated $1.8 million to fund the renovations, which include new bleachers, a digital scoreboard and upgraded facilities. The stadium is dedicated to William Clay Ford Sr., who passed away in March.
"This couldn't have been a more perfect event to honor him," said Bill Ford, executive chairman of the Ford Motor Company. "It's awesome to have now two Ford Fields in Detroit. I hope we see winners in both of them very soon."
The festivities began with a performance by the Martin Luther King High School Band, followed with a ceremonial ribbon cutting and comments from Ford and mayor Mike Duggan, among others.
UAW-Ford vice president Jimmy Settles, whom Duggan called the "driving force" behind the renovations, spoke of a desire to make baseball more popular in inner-city communities. William Clay Ford Field will be put to use right away, hosting its inaugural game on Monday afternoon.
"Maybe we'll see the next Willie Horton playing right on this field," Duggan said.
Alejandro Zúñiga is an associate reporter for MLB.com. Follow him on Twitter @ByAZuniga. This story was not subject to the approval of Major League Baseball or its clubs.