Judge Katherine Failla of the Southern District of New York said Elliott and his NFL Players Association legal team failed to demonstrate a substantial question warranting the extraordinary remedy of injunctive relief, forcing him to begin his six-game suspension immediately.
Moreover, the court ruled that the NFL was fair in its investigation and arbitration process per the terms of the collective bargaining agreement and the league's personal conduct policy.
Elliott has 24 hours to file an emergency appeal.
What it means now is that Elliott must immediately begin serving his suspension while the full case plays out in the Southern District Court.
He'll be eligible to return on Dec. 17 against the Oakland Raiders.
It's a huge setback for the Cowboys (4-3), who have won two straight games after a disappointing 2-3 start, especially with last season's leading rusher seemingly finding his old groove again.
Elliott, who currently ranks third in the league in rushing with 690 yards, had a career-high 33 carries for 150 yards in Sunday's 33-19 victory against the Washington Redskins. It was his third straight 100-yard game and third career game over 150 yards dating back to last season.
Head coach Jason Garrett said the Cowboys built their roster knowing suspension was possible.
"We have some veteran running backs, we have some depth at that position," Garrett had said earlier on Monday. "It's not like we're just living this day and we don't think about the future at all -- you have to do that. I think you build your team that way at all positions. If this guy is not able to play, who's your backup? Who can go in? That's the way you construct your team, and you're always thinking about those scenarios.
"We'll take it one day at a time and we'll see what his situation is. Regardless, we're going to go forward and try to play our best football."
This case and the fallout, however, are far from over.
It will get even more intense with Cowboys owner Jerry Jones, who believes the NFL should get out of the investigation business and leave that to the court system.
Elliott was never arrested or charged in the case as the Columbus (Ohio) City Attorney cited inconsistent and misleading testimony, yet the NFL believes it has evidence of three instances of domestic violence when it made its initial decision to suspend Elliott Aug. 11.
"What is important is that he gets a fair shake," Jones said. "Zeke has in no way by any standard in this country done anything wrong. He's done nothing wrong. We believe the league has tried to say that he's done something that we disagree with; we all don't agree with that. I want him to get a fair shot; he deserves that.
"We don't have the system in place for this. We tried to make one up in a few short months and it's got too many ways to not be fair for a person like Zeke. I know this, we have a pretty good system in place in this country. It's called the legal system. It has a lot of precedents and its made a lot of mistakes, but it's the best one in the world, in my view. For us to not basically recognize that, that's a concern."
--Kicker Mike Nugent tried out for the Washington Redskin earlier this month, but they opted to go with former Texas kicker Nick Rose. That kept Nugent on the open market, and the Cowboys signed him last week after Dan Bailey went down with a groin injury.
Nugent made the Redskins pay in his debut, connecting on four of five field goals and all three extra points in a 33-19 victory over the Redskins on a rainy afternoon at FedEx Field.
"It is satisfying," Nugent said. "I have had about five or six workouts in the first eight weeks and I felt like I hit the ball really solid in training camp. It's good to get out on the field and it's a positive feeling to be able to feel like you contributed to a win today. I'm about that."
It didn't get off to the best start, though. Nugent's first field-goal attempt from 49 yards was wide left.
But he responded by connecting on four second-half field goals of 36, 48, 27 and 37 yards. Considering the weather factor, Nugent has earned trust quickly.
--The Cowboys' pass rush used to be a weak link. Now it's one of the strengths of the team in the first seven games this season. The Cowboys have the fifth-most sacks in the league with 25 and are on pace for 57. The Cowboys haven't reached the 40-sack mark since 2011.
"Obviously impacting the quarterback is one of the most important things you can do to play good defense," Garrett said. "Quarterbacks in a comfortable environment in this league can really hurt defenses, so what you're trying to do is make them uncomfortable.
"I think on a consistent basis our guys have been able to do that and it certainly helps you play good defense. Not only have they pressured them, they sacked them and particularly in the game yesterday I think they caused some turnovers, which is the most important thing you can do on defense."
The Cowboys' pass-rush resurgence starts with DeMarcus Lawrence. He is finally healthy and is leading the league with 10.5 sacks. He's already set a career high and is the first Cowboys player to reach double digits in sacks since Jason Hatcher had 11 in 2013.
Lawrence had another sack Sunday, and has yet to go a game without one. His teammates are feeding off his production, too. David Irving has five sacks in three games.
The Cowboys had 14 sacks in seven games and didn't get their 25th sack until Week 14 at the Giants last season. They finished with a respectable 36 for the season, but are on pace to better that by 20 this season.
The Cowboys had 42 sacks in 2011. They had 36 sacks last season, 31 in 2015, 28 in 2014, 34 in 2013 and 34 again in 2012.
NOTES: WR Cole Beasley suffered a concussion against the Redskins and is questionable for the Chiefs game. ... DT Tyrone Crawford had a blocked field goal, a sack and forced fumble in a monster game against the Redskins. ... FS Byron Jones' second career interception was a doozy as he returned it 21 yards for a touchdown. It was a testament to his offseason work to improve his pass-catching skills. He even caught fly balls during batting practice with the Frisco RoughRiders, a Double-A baseball team, to improve his hand-eye coordination. ... CB Orlando Scandrick had a monster game against the Redskins with eight tackles, two tackles for losses and an 86-yard blocked kick return. He didn't score, but he was OK that running back Ezekiel Elliott got the touchdown because he is on his fantasy team.
REPORT CARD VS. REDSKINS
--PASSING OFFENSE: C -- Dak Prescott's performance was not something he is proud of, but the bottom line is that he got the win. He completed 14 of 22 passes for 143 yards. The best he did was not turn it over. Prescott completed just five passes in the second half. The wet conditions played a factor as receiver Dez Bryant dropped a touchdown pass. It was strange because Prescott opened the game 6 of 6 and completed nine of his first 10 passes for 105 yards.
--RUSHING OFFENSE: B -- The only reason the Cowboys don't get an A is that Ezekiel Elliott had a fumble on the opening play of the game and tackle Tyron Smith negated an Elliott touchdown run with a holding penalty. But Elliott did yeoman's work in the rain, rushing 33 times for 150 yards. It was a career high in carries and it was the third game in his career with at least 150 yards. It was also his third straight game with over 100 yards.
--PASS DEFENSE: A -- The Cowboys recorded four sacks and got a tipped pass interception return for a touchdown from safety Byron Jones. David Irving had two sacks. Tyrone Crawford had a sack and a forced fumble. DeMarcus Lawrence had a sack and a recovered fumble. Orlando Scandrick had eight tackles and two tackles for losses. Certainly, Redskins quarterback Kirk Cousins had his moments with a number of big plays, completing 26 of 39 passes for 263 yards and a touchdown. But he had no chance against the Cowboys' pass rush with the Redskins banged up offensive line.
--RUSH DEFENSE: B -- The Redskins rushed 15 times for 49 yards. They got 8 for 19 from Rob Kelley. And while Chris Thompson had 18 yards on four carries, one was for 16 yards. Linebacker Sean Lee keyed the run defense with a team-leading nine tackles. But this was a collective effort with defensive end David Irving recording two tackles for losses. Defensive lineman Richard Ash and DeMarcus Lawrence had one each.
--SPECIAL TEAMS: A -- While Ryan Switzer continues to be a curiosity on returns because of a litany of poor decisions, the special teams won the game for the Cowboys. Mike Nugent kicked four field goals in his first game as an injury replacement for Dan Bailey. Tyrone Crawford turned the game around with a blocked field goal attempt and Orlando Scandrick's 86-yard return. And fullback Keith Smith forced a fumble on a kickoff, recovered by cornerback Bene Benwikere that led to a field goal.
--COACHING: B -- Give Jason Garrett credit. He has the Cowboys riding the momentum of a two-game winning streak following that 2-3 start. And even after a slow start against the Redskins, he kept the Cowboys aggressive and focused on burying an injury-challenged opponent.