This is the first time William, 23, has become patron of a charity, a role familiar to most senior royals.
William has been familiar with the work of Centrepoint since his childhood, when his mother took him and his brother, Prince Harry, to visit one of the charity's night shelters.
"I have always been deeply concerned for those people — especially young people — who, for whatever reason, find themselves living on the streets or without a proper home," William said Tuesday in a statement.
He had spent the last two days volunteering with the charity.
Diana became patron of Centrepoint in 1992 and remained in the role even after she scaled down many of her other charitable activities.
In January 1996, when William was 13 and Harry was 11, their secret trip to meet residents at a night shelter in Soho, central London, was leaked to the media.
During their hour-long visit to the hostel, the young princes met the 25 teenagers staying there, talking to them in the canteen and listening to their problems.