The Impact sent popular midfielder Felipe to the Red Bulls for left back Ambroise Oyongo and veteran midfielder Eric Alexander.
The trade completes a near-total remake of the back line for a team that allowed 58 goals last season, third worst in Major League Soccer.
"We feel it's in our favour, that we improved the squad," Adam Braz said after his first deal since he was named the Impact's technical director on Nov. 24. "They wanted Felipe and they gave up a lot to get him."
The Impact should begin the campaign with a back line of returning Frenchman Hassoun Camara at right back, Ciman and newcomer Bakery Soumare in the middle and Cameroon international Oyongo on the left side.
"The whole back line speaks French now, so there's no reason they can't communicate with each other," quipped coach Frank Klopas.
Later Tuesday, Montreal acquired Ghanaian winger/forward Dominic Oduro from Toronto FC in return for allocation money.
Montreal also got allocation money and an international roster spot in the New York deal while the Red Bulls got the top spot in the allocation order, which may be the key to the deal. It gives the team who holds it first dibs on any U.S. national team player who wants to return to MLS from an overseas league.
The league website mlssoccer.com reported New York may be interested in midfielder Sasha Kljestan, currently playing for Anderlecht in Belgium. Kljestan was once a teammate of Red Bulls coach Jesse Marsch.
It was Marsch who brought Felipe to Montreal for its expansion season in 2012. The 24-year-old became a workhorse for the Impact, scoring 12 goals and adding 24 assists in 93 games over three campaigns.
There was speculation Felipe may be traded because of a glut of attacking midfielders. There was also concern from some that he had not progressed since his rookie year, which made the Brazilian bristle.
"You check my statistics: the past two years I did almost the same from my first year," said Felipe. "Which player played more minutes than me? (none). Which player had more passes than me? Who creates more than me?
"Even birds can talk but, in the end, it's what you did (that counts). I'm leaving with my head up because I know I did everything I could for this club."
Left back was a revolving door for Montreal after Jeb Brovsky was traded early last season and the Impact hope to have fixed that with Oyongo, backed up by former Chivas USA back Donny Toia. Oyongo is currently playing in the African Cup of Nations, where he scored against Mali on Jan. 20.
"He's a tremendous young talent, attack minded, a lot of pace and technical ability," Klopas said of 23-year-old Oyongo, who played 13 games as a rookie for New York last season. "He gets forward.
"That's the kind of player we were looking for on that side with the way we want to play."
Some European clubs have shown interest in Oyongo, so he may draw a tidy transfer fee sometime in the future, Klopas added.
The surprise was landing Alexander, a 26-year-old American who started 60 of 68 games over the last two seasons, scoring six goals.
In Montreal, he will compete for playing time with designated player Ignacio Piatti, Andres Romero, Justin Mapp and Dilly Duka. His versatility will come in handy, said Braz.
"Alexander has played out wide and in the middle for New York," he said. "He was an important piece of the puzzle for them. He's got experience and he's at a good age."
Alexander, who has played twice for the U.S. national team, is expected to fly in from the Red Bulls camp in Orlando, Fla. on Wednesday.
The Impact had already beefed up the holding midfield positions with the addition of veterans Nigel Reo Coker and Marco Donadel.
Returnee Jack McInerney was the club's lone experienced forward before the Oduro trade. The deals overshadowed the arrival of Ciman, who scored a rare goal in his final game for Belgian club Standard Liege on Sunday.
The 29-year-old got a free transfer from Standard so he could play in North America and get specialized treatment for his autistic four-year-old daughter that was not available in Belgium.
The Impact were able to work out a deal in which Ciman does not use up one of the three spots per team allowed for designated players.
"Certain things fell into place at the right time," said Braz. "We're lucky, but excited to be able to bring a player of his calibre to the club."