The Rev. Al Sharpton turns 60 this week, reaching a milestone in both his professional and personal life. Once known primarily as a polarizing civil rights leader, Sharpton is at the height of his influence, advising some of the most powerful leaders in the nation — President Barack Obama and Mayor Bill de Blasio — and bolstering his position as the go-to voice for African American community leadership.  

Peniel Joseph, professor of History at Tufts University and the author of several books about the civil rights movement, said Sharpton continues to be a catalyst for action. 

"He’s transformed the discourse, because 20 years ago, we weren't talking about putting cameras on every single cop, where as now we got a mayor and police brass who are willing to talk to somebody like Al Shapton about ways that police-community relations can be better in a matter that they wouldn't have in a previous historical context," Joseph said. 

He spoke to WNYC's Amy Eddings about Sharpton's career evolution.