The judge, who is based in Rhode Island, also criticised President Donald Trump for saying that benefits would only be distributed after the government shutdown ends.
He granted a request from several local governments and non-profit groups that asked that the government provide full food benefits, rather than the 65% that had been ordered to be paid out this month.
Judge McConnell, who was appointed by President Barack Obama, ordered that benefits be paid by Friday, adding that any further delay would be “simply unacceptable”.
“This should never happen in America,” he continued.
More than 42 million Americans received Snap benefits, however the programme has been in limbo during the more-than-month-long shutdown.
While individual US states administer the benefits, the programme relies on money from the federal government, which has been unfunded and shut down since 1 October.
Late last month, the US Department of Agriculture (USDA), which runs Snap, said it would not distribute food-assistance funds starting 01 November because of the shutdown, saying: “The well has run dry.”
Half the states and the District of Columbia sued the administration over the food-aid freeze and argued that they had a legal obligation to keep the programme running in their jurisdictions.
Federal judges in Massachusetts and Rhode Island ruled that the administration needs to use $5.25bn (£4bn) in emergency funds to make at least partial payments to Americans.
Snap costs about $8bn per month and allows many low-income Americans to buy groceries. It provides them reloadable debit cards that they can use to buy food.
A family of four on average receives $715 per month, which breaks down to a little less than $6 per day, per person.
Amid the uncertainty over Snap funding, local governments have been helping direct recipients to charity food pantries which have been holding emergency drives.
Cost-saving recipes have also gone viral online, as Americans search for ways to stretch their budget.
