Sean Plunket has resigned as a member of the Broadcasting Standards Authority (BSA).
It comes only days after the veteran journalist made a controversial tweet which appeared to support disgraced Hollywood movie producer Harvey Weinstein.
Weinstein has effectively been forced out of the movie business over recent days and has seen his marriage crumble, under a barrage of sexual harassment charges from high-profile actresses and models.
On Wednesday, Mr Plunket tweeted "Anyone else feeling for Harvey Weinstein?", drawing howls of protest from throughout the Twittersphere.
He later backtracked, claiming his post was a "little social experiment", then tried to deny all knowledge of it before finally taking responsibility for the comments.
"So my feelings for Weinstein are revulsion, anger and contempt. Wonder if this tweet will get covered in the herald."
Mr Plunket was recently appointed to the BSA, a body charged with upholding "good taste and decency" in the television and radio industry.
But on Friday he resigned "in the interests of the smooth running of the Broadcasting Standards Authority".
"I have chosen to resign my position as a member of the BSA Board. I wish the Board well in its important work in ensuring that the broadcast media in this country adhere to practices which do not harm society in general or individuals in particular," Mr Plunket said in a statement.
BSA chair Peter Radich says the board "respects" Sean's decision.
"Sean Plunket is an experienced journalist and broadcaster whose contributions are part of the recent fabric of broadcasting… We wish him well for the future."