Kamara left Kansas City for a brief loan spell with Premier League side Norwich City in the winter before returning to the States three months later.
The former Columbus Crew and San Jose Earthquakes attacker then signed a contract with English Championship club Middlesbrough in early September and upon his departure, wanted to thank Sporting Kansas City fans for all their support during his time with the club.
"I wanted to do a video because since I left, I didn't get to say properly that I was leaving and it took me by shock too that I was leaving Kansas City, a place where I've been for four years," he said on the Youtube clip.
"A place where I call home in America, so it's a tough one."
Watch the video here: http://www.youtube.com/watch?v=0Q5BZbObiPs