Alphard was a man with a full beard, always wearing a top head and he had icy blue eyes, which is unusual in the normally dark-eyed Black family.
Judging from Alphard's action, helping his nephew when he ran away from home, it can be deduced that he was, at the very least, capable of love and fondness; and he might have been kind and compassionate in his life, vastly different from his sister. He did not seem to fear being blasted off the tapestry, indicating that he had a rebellious or brave bone in himself.
He was born in 1930 and attended Hogwarts from 1941 to 1948 and was sorted into Slytherin House. When he died in 1977 in a pub fight, he left much to his run-away and hisinherited nephew, Sirius Black III, leading him to be disinherited too.