Ma and Trump met in January 2017 to discuss how adding small and medium-sized USA businesses to Alibaba's platform would boost employment.
But Ma told Xinhua that his pledge had been made on the basis of continued cooperation and trade growth between the U.S. and China, and would now be hard to fulfill.
Given China's counter-tariffs and the push for Chinese firms to find alternative, non-US sources for goods, the already optimistic pledge would be even more unlikely in the current environment.
In an interview with Chinese outlet Xinhua, Ma said recent back-and-forth tariffs between the United States and China made the pledge - which was heavily touted by Trump in the early days of the transition period - unworkable.
Ma's remarks come a day after U.S. President Donald Trump announced his decision to impose additional tariffs on $200 billion more in Chinese goods starting next week.
The economic situation is not good, and that could last for a long time, Ma said at the World Economic Forum in Tianjin.
South Africa legalises cannabis use
These are all popular misconceptions and people should inform themselves with the truth. The court gave parliament 24 months to change the law to reflect its ruling.
Ma also said that trade should be used as a tool for peace rather than a weapon.
Ma made his commitment on January 9, 2017, prior to Trump's inauguration in a meeting at Trump Tower in New York City.
One million jobs would be close to 1 per cent of all jobs in the United States - meaning that successfully delivering on the pledge would make Alibaba one of the country's largest private employers.
"It's going to be long-lasting, it's going to be a mess, maybe 20 years", Ma said.
Tensions have escalated this week as China vowed to retaliate against USA plans to levy tariffs on about $200 billion in Chinese goods.
Mr Ma pointed to business opportunities in other regions such as Europe, South America, Russia and Africa, Xinhua said.
The tariffs imposed by the U.S. are set to come into effect from September 24 with the 10% level, which will be increased to 25% from next year. On Monday, Trump announced a 10% tariff on another $US200 billion worth of Chinese goods.