Updated Friday, May 13 5:44 p.m.
NEW YORK (CBSNewYork) -- He already has four World Series rings and a batting title, now Bernie Williams is adding a college degree to his list of accomplishments.
A decade after retiring from the Yankees, the star center fielder earned his Bachelor of Music in three years from the Manhattan School of Music.
After ending his baseball career, going to college was a no-brainer for the now 47-year-old.
"I thought it was really important for me," Williams said. "My mom was an educator for 40 years in the public education system in Puerto Rico. ... Academics were really high in my house. You earned the right to play baseball and play music if you had good grades. That was the rule."
Williams' hits used to come with a bat at the ballpark, now they're played on the guitar.
"It was really challenging," Williams told CBS2's Steve Overmyer of the experience. "I thought I knew how to play guitar before I came here.
"The cool thing about this is there are no stats for wrong notes," said Williams, who already had two Latin Grammy nominations before he started at the school.
Williams received high praise from school officials.
"Bernie Williams the music student is one of the most humble, wonderful, hardworking guys that you would ever find in a music school anywhere," school President James Gandre said.
"If you had no idea who he was beforehand, you wouldn't have a clue if you just followed him around," said fellow graduate Ryan DeWeese. "He seemed like a regular student. And then it's like, 'Oh crap, this Yankees Hall of Famer's here."
"For me, it was like if a superstar like him has that sort of humility, who am I to ever have any sort of ego," said Tom Wilson, another member of the Manhattan School of Music Class of '16.
Williams spent 16 years with the Yankees. He first signed with the team when he was 17 years old.
"Most of these great musicians weren't even born when I was playing baseball," Williams said with a laugh. "And I think in a way I feel that I needed to earn their respect, not for what I did before but for what I'm doing now."
Williams said he's working on his third album and will perform later this month at the White House for President Barack Obama and the first lady.
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