“Securing a spot for the Olympics should be passed purely on skill and merit,” said Jonathan Greenblatt, the ADL’s chief executive in a letter.
“We therefore urge your organization to reconsider its determination and make concerted efforts to allow Estee to compete.”
Ms Ackerman first made headlines in the summer of 2013 when, aged just 11, she defeated Spanish tennis star Rafael Nadal.
Nadal, in the prime of his career, went on to win the US Open hard court tennis tournament a few weeks later.
Table tennis trials for this summer’s Olympic Games are due to take place in California later this month but a registration deadline passed last Saturday without a decision to allow Ms Ackerman to compete.
Her father Glenn had contacted USA Table Tennis in January asking for games to be scheduled on Thursday, before sunset on Friday and on Sunday, the New York Post reported.
She told the newspaper: “I’m confused why they won’t work with me. I’m serious and dedicated. I enjoy the toughest of the toughest competition.
“I would love to go to Tokyo [for the Olympics] this summer. I think I should get the opportunity to try out.”
