The musician was appointed to his post Friday. He said the title is humbling but fits his humanistic goals. Hancock said he expects to use his music to build bridges across cultures.
He is already working on an international Jazz Day that could begin as early as next year.
He sees jazz as a "metaphor for freedom but freedom with discipline" that can be used to connect cultures and promote excellence and literacy.
Hancock, whose signature pieces include "Chameleon" and "Watermelon Man," has adapted his music in a half-century-long career and says that at 71 his UNESCO post gives him a new lease on life. He says, "I've just started."
The Associated Press contributed to this report.