Donald Edmond "Donnie" Wahlberg Jr. (born August 17, 1969) is an American singer, songwriter, actor, film producer, and music producer. One of his brothers is actor Mark Wahlberg, and he himself is married to comedian and actress Jenny McCarthy.

He is one of the founders of the popular 1980s and 1990s boy band New Kids on the Block.

He is best known for his television role as Detective Danny Reagan in the series Blue Bloods, for which he was nominated in 2017 for a People's Choice Award in the category of Favorite Crime Drama Actor. He is also known for his roles as Donnie in the sitcom The Return of Mack, Detective Horst Cali in Kill Point, Paul Rader in The Fugitive, Detective Joel Stevens in Boomtown, Lieutenant C. Carwood Lipton in the award-winning miniseries Band of Brothers, and Chris Scott in The Big Apple.

Graham Yost, executive producer and writer of Boomtown, worked with him on Band of Brothers and was so impressed by his performance that he specifically wrote the role of Joel Stevens for him.