Susan McIntosh said Tartan Day had no significance for Scots, was poorly-attended, and barely noticed by the media.
Ms McIntosh, until recently the president of the North Carolina-based Council of Scottish Clans & Associations, said the event should go back to the drawing board.
The 17th parade took place through the streets of the city on April 11.
Designed to appeal to the 14 million Americans who claim Scottish ancestry, the event is possibly best known in Scotland for former First Minister Jack McConnell’s decision to attend wearing a pin-striped kilt and Jacobite shirt.
Ms McIntosh, writing in Scots Heritage magazine, claimed the event was an “unfortunate mongrel of a commemoration”, “poorly attended” and “media thin” compared with other “ethnic hoedowns”.
According to Ms McIntosh, part of the problem for the Scots-American celebration was a decision by congress in 2008 to officially anoint April 6 as a Tartan Day based on a “flawed interpretation” of the US Declaration of Independence.
“The line connecting the Declaration of Independence and the Declaration of Arbroath is faint at best and totally made up at worst,” she said.
“Yet it is the line that dominates our celebrations.”
To make matters worse, this year’s parade had been held on April 11 - a “day of no significance to Scots”.
Ms McIntosh, secretary of the board of the Clan McIntosh North American Society, added: “Let’s start over. Let’s think bigger. Let’s begin from the ancestral Scottish grassroots and build upward.
“Let’s work with Scots all across the globe to craft a Scottish celebration of which we can all be proud.
“How about a global Outlander Day?”
An Edinburgh-based promoter agreed with Ms McIntosh and said that Tartan Day “doesn’t resonate with young Scots”.
The promoter, who asked to remain anonymous, added: “I know young designers who won’t go to Tartan Week because it’s just not relevant.”
However, Alan Bain, chairman of the American Scottish Foundation - the organiser of New York’s Tartan Day parade - insisted Ms McIntosh’s views were “misguided” and “misinformed”.
He said that this month’s event was their “biggest parade ever” with contingents from eight Scottish universities marching, which showed that it was relevant to contemporary Scotland.
However, one million people turned out to watch New York’s Columbus Day parade to celebrate the Italian-American culture.
Twice as many again turned out to commemorate St Patrick’s Day.