The 23-year-old Mitrita, who turns 24 on February 8, arrives from Romanian top flight side Universitatea Craiova, where he has spent the past two and a half seasons after making the move from Italian side Pescara.
NYCFC announced Mitrita has signed a multi-year contract with the team, and though terms of the transfer were not disclosed, reports have put the fee at around $9 million (£7m).
“Alexandru is a very talented attacking threat who can score goals and create chances when running at the opposing team,” NYCFC sporting director Claudio Reyna said in a statement. “At almost 24, he’s part of an exciting younger generation coming out of Romania.
“He comes to New York during a stage in his career where he’s extremely motivated to make the next step after recently breaking into the Romanian national team.”
Mitrita can feature across the attacking front as a midfielder, winger or forward, and previously played for Turnu Severin and Viitorul in the Romanian top flight before making the move to Pescara, at that time in Serie B, in the summer of 2015.
He would feature 19 times in Serie B for the Italian club in his first season, mostly as a substitute, as Pescara won promotion to the top flight.
Mitrita would play another 15 times for Pescara the next season in Serie A, before he returned to Romania that summer with Universitatea Craiova, first on loan and then permanently.
This season has seen a break out for the attacker in the league, as he has netted 13 times in the Romanian top flight in 18 league games, eclipsing the 12 league goals he scored in his previous two seasons with the club.
He has also been capped six times by the Romania national team, having debut in March 2018.
Mitrita joins Maxi Moralez and Jesus Medina as NYCFC’s designated player – a role previously held by David Villa, who left the club on free transfer after four years in the league.