Henry attends Storybrooke Academy along with his cousins, Roland, Robin and Grace. He is the second oldest of the Mills children after Roland. He and Roland are in the tenth grade.
Biologically, He is the child of Regina Mills and Neal Cassidy. Regina had one of her eggs fertilized and implanted into Emma's womb.
As none of his parents are married, Maleficent (Regina's best friend and on and off girlfriend) is his godmother.