The 30-year-old's 7-6 6-1 demolition of 2008 Auckland champion Philipp Kohlschreiber in 78 minutes ensured the Spaniard joined Australia's Roy Emerson as the only four-time winners of the title.
Ferrer won his first Auckland title in 2007 and has won the last three editions of the tournament.
His victory ensured he become the second player, after Emerson, to win the title in three successive years. The Australian won his four titles in 1960 and then again from 1965-67.
"It was amazing for me to win here. Four times now, I can say this is my favourite tournament for sure," said Ferrer.
"Of course it is never easy to win an ATP tournament - and to win four times, is more difficult. I want to enjoy this moment because it is very special to me."
Ferrer will now travel to Melbourne for the Australian Open where he meets Belgium's Olivier Rochus in the first round.