Klich recently agreed to terminate his contract at Leeds in order to make the move to the United States.
A firm fan favourite at Elland Road, the Polish midfielder was given a guard of honour when he left the pitch for the final time in a white shirt.
He has now sealed a move to DC United, where he will play under Wayne Rooney in the MLS.
Klich is joining DC United as a Designated Player.
The midfielder will now prepare for the new MLS season, with DC United hoping to hugely improve on their showing last term.
They finished rock bottom of the Eastern Conference, with just seven wins from 34 league games.
Klich made a total of 195 appearances for Leeds during his time at the club and helped the Whites to win promotion to the Premier League.
