Gerard Culhane (43) replied "no, I accept the charge", after gardaí put the allegation to him.
As part of his bail conditions, he has been ordered to have no contact, either directly, indirectly or on social media, with Ms Carroll MacNeill.
Judge Conal Gibbons remanded Mr Culhane on bail to appear before Dún Laoghaire District Court in September.
The accused, of Marian Place, Glin, Co Limerick, is charged with harassing the Fine Gael TD at places unknown within the State on dates between January 13, 2020, and March 26, 2020.
Detective Sergeant Rachael Kilpatrick told Dublin District Court that she met Mr Culhane by appointment at Dundrum garda station on Tuesday afternoon and charged him with the offence.
Det Sgt Kilpatrick said Mr Culhane was handed a true copy of the charge sheet and in reply after caution, he said "no, I accept the charge".
The sergeant said she had no objections to bail, subject to a number of conditions.
Judge Gibbons remanded Mr Culhane on bail in his own bond of €200.
As part of his bail conditions, Mr Culhane must sign on once a week at his local garda station.
He must have no contact with the alleged victim or any witnesses in the case.
Mr Culhane has been ordered to reside at his home address and inform gardaí of any change in address. He must also provide gardaí with a mobile number.
The court heard Mr Culhane was unemployed and defence solicitor Eddie O'Connor was assigned on free legal aid.
Det Sgt Kilpatrick said the DPP had directed summary trial of the offence in the district court.
Judge Gibbons ordered the disclosure of any statements in relation to the allegation to the accused's lawyer.
Judge Gibbons said jurisdiction can be considered on the next date. Mr Culhane has not yet indicated a plea to the charge.
Ms Carroll MacNeill was elected as a TD in Dún Laoghaire in February 2020.
She is the vice chair of the Fine Gael parliamentary party and its spokesperson for equality.
She was selected internally by the Fine Gael branch in Dún Laoghaire to replace former TD Maria Bailey on the ticket for the general election in 2020, following 'Swinggate', a controversy over a legal claim made by Ms Bailey that resulted in her subsequent deselection.
Ms Carroll MacNeill is married to rugby international Hugo MacNeill, who is expected to run in the upcoming Trinity College Seanad by-election to fill the vacancy left after Labour senator Ivana Bacik's election to the Dáil.