In an interview on Thursday, Ms Harris said that Doug Emhoff will take the title, clearing up speculation as to what he would be known as, being the first male to be the spouse of the vice president.
Previous spouses have been known as “second lady”.
The Associated Press has already been referring to Mr Emhoff as second gentleman, but there had been no official word from the Biden-Harris transition team.
Speaking with CNN’s Jake Tapper, Ms Harris said: “I think that the term has evolved into the second gentleman.”
Mr Tapper joked about referring to Mr Emhoff as “the second dude” to which Ms Harris responded that some of his friends would be inclined to say that.
“But you’ll call him the second gentleman?” asked Mr Tapper.
“No, I’ll call him honey,” laughed Ms Harris.
Mr Emhoff is a partner at law firm DLA Piper, but will leave by the inauguration on 20 January. He is reportedly working with the transition team to establish what role he will play in the administration as the first man to hold the position.
A Biden official told Fox News that Mr Emhoff was "working with the Biden-Harris transition team to develop the portfolio he will focus on to support the work of the administration."
Mr Emhoff joined DLA Piper in 2017 where he works with media, sports, and entertainment clients, as well as intellectual property and technology, litigation, arbitration, and investigations.
He has said that he has no interest in joining a “kitchen cabinet” of advisers to his wife, saying that she has great people advising her already.
The couple met on a blind date in 2013 and married a year later. Mr Emhoff has two children from a previous marriage to film producer Kerstin Emhoff.