The actor and his wife Jessica welcomed their first child Noah in July, but Lucas told Access Hollywood that he can't get a good picture of his son.
"My child so far is remarkably unphotogenic," he said. "It's quite weird.
"My mother-in-law and I were laughing about it the other day. It was like, he's a great-looking kid, but every photograph he just looks like this bizarre baby."
However, Lucas added that being a father is "the most amazing thing".
"I will go sleepless and die for this child already," he said. "And I'm still dealing with a blob... I'm still dealing with something that's just now beginning to communicate through smiling and through these magical little moments that happen only very briefly through the day.
"But it is a truly magical, amazing thing and the emotion and the sense of wonder that goes along with it, it's incomprehensible until you do it. I'm having a ball."
Watch Josh Lucas talking about fatherhood to Access Hollywood below: