William "Billy" Black, Jr. was born in and is a lifelong resident of La Push, Washington. He is the son of William "Billy" Black, Sr. and Judith Peterson. He is the father of Jacob, Rachel, and Rebecca. His wife, Sarah died in a tragic car accident.
He is the oldest grandson of the legendary last official chief of the Quileute Tribe, Ephraim Black. After his death, he became chief of the Quileute Council.
Billy is wheelchair-bound due to complications from diabetes.
He is best friends with Charlie Swan, Bella's father, but can't reveal the Cullens' secret about being vampires or his tribe's secret about wolves. He worries about Bella's safety as well as her relationship with Edward, and even tries to have his son, Jacob try to talk to Bella about breaking up with him. Billy is devastated when Bella chooses Edward. He attends their wedding, but is still sad about Jacob's broken heart.
Billy is responsible for passing down the traditions of the Quileutes to the next generation, including his 3 children. Part of the histories include the shape-shifters. While a wolf, Ephraim Black's main role to play was to protect the tribe from enemies of any kind, including the blood-drinking cold ones. Somewhat vexed by the Cullens' choice to only drink the blood of animals, Ephraim, a man of justice, chose to make a treaty with the Cullens. He chose not to reveal them as vampires as long as they stayed off the Quileute Tribal Lands and not bite humans. After his death, Billy had become the protector of that treaty, always worrying about the Cullens breaking it.
Sam Uley was the first Quileute in 2 generations with the gene to phase into a wolf. Billy, along with the tribal leaders, help guide Sam through the changes in his life. Sam, at this time being the only wolf, becomes de-facto Alpha. Once Billy's own son, Jacob Black, phases into wolf form, he becomes rightful Alpha leader of the Quileute people. Jacob, however, denounces his title to Sam until Sam decides to kill Bella and her unborn baby in Breaking Dawn.
His daughter, Rebecca married Solomon Finau, a Samoan surfer from Hawaii when she turned 18, and moved to Hawaii with him.
His daughter, Rachel was imprinted on by Paul Lahote, which annoyed both Billy and Jacob, because he's always at their house taking up most of the room on the sofa, controlling the TV and eating their food. Billy is happy that Rachel decided to stay in La Push because of Paul.
His son, Jacob imprinted on Renesmee Cullen, which brings permanent peace to the Cullens and wolf packs.