Endymion, King of the Earth
Chibiusa's obsession with her dear papa is explored further in the manga than it is in the anime, up to the point where she abducts her father's past incarnation and makes him her boy toy while under the influence of evil. A child's obsession with the parent of the opposite gender is a pretty common thing in a child this age, so her desires to marry him shouldn't really be taken seriously.
Whatever the case, Chibiusa loves her father dearly. She is very much a daddy's girl since presumably he has a little more time to lavish on her than her mother does. He also probably seems more approachable since Chibiusa doesn't aspire to be him when she grows up. He's also the one who told her stories at bedtime growing up, and the impression is strong that he was the one largely in charge of Chibiusa's upbringing. She loves him and respects him and desperately wants to make him proud, but he seems a softer touch than Neo Queen Serenity, which isn't really surprising since the weight of the world is on her shoulders.