The 32-year-old and his wife Aryn Drake-Lee welcomed a daughter, Sadie, in December 2013.
"It's hard to describe. It's wonderful - a new discovery every day. It's great and I'm loving it," people.com quoted Williams as saying.
The "Grey's Anatomy" star also admitted that he is a bit sleep-deprived.
"Not getting too much sleep...I'm just trying to put together three solid hours of cogent communication!" he said.
He was at the 71st Golden Globe Awards as a member of Lee Daniel's "The Butler".
--IANS (Posted on 13-01-2014)