Al Hanks is Clair Huxtable's father, married to Carrie Hanks. He was played by jazz singer Joe Williams.
Al appeared in three episodes total:
-Clair's Sister, where we see that he enjoys playing chess. Also, he and Clair sing a rendition of "We Belong Together", which he plans to sing at Sarah Hanks' wedding.
-The March, where he sings "The Battle Hymn of the Republic"