The 21-year-old struck his second goal for Huddersfield on his first start for over a month in Saturday's 4-0 win after being given his chance ahead of Theo Robinson alongside leading goalscorer Jordan Rhodes.
Clark said: "Lee cost a minimum amount of money and is desperate to prove himself as a league footballer. We are delighted to have him here.
"He will have ups and downs because of the environment he's come from and I need to be careful of that, but what he has is unbelievable energy and a great work ethic. He has given me food for thought again."
The Terriers beat off several clubs during last January's transfer window for the signature of Novak, who had scored 17 goals in 19 appearances for Gateshead.