The Sabres forward shoved Rangers centre Brad Richards from behind and into the boards on Sunday night.
The suspension will cost the gritty right winger more than $72,000 in salary, and he won't be eligible to return until March 17, when the Sabres play at Washington.
The ruling came down a day after Kaleta blindsided Richards in the back and sent him sliding headfirst into the boards in the third period of Buffalo's 3-2 shootout loss at New York. Kaleta was assessed a major penalty for boarding and a game misconduct, which resulted in an automatic review by the league's department of player safety.
In reviewing the play on a video posted on the league's website, NHL disciplinarian Brendan Shanahan noted Kaleta shoved a defenceless player from behind. He added, "Kaleta is in full control of this play, and has ample opportunity to make a better decision."
Shanahan took into account that Richards was shaken up, but returned soon after. He also noted Kaleta had been suspended twice before in his career.
The suspension is one game longer than the suspension handed out to Philadelphia Flyers forward Harry Zolnierczyk a day earlier. Zolnierczyk was suspended four games without pay for a charging penalty against Ottawa Senators defenceman Mike Lundin on Saturday.
Kaleta is one of the Sabres' top penalty killers, and noted for his aggressive style. He has no points and a team-leading 46 penalty minutes in 18 games this season.
The Sabres (9-12-2) are in the midst of a four-game road trip, and play at Carolina on Tuesday.