In the Rhinos opening three Super League games, wins over Hull and Salford plus a defeat against Castleford, Sinfield landed 15 from 15 attempts at goal.
It earns him the first monthly prize of the season, £100 worth of match balls to be donated to a junior club of his choice.
Tony Colquitt, Managing Director of Rhino Rugby League, said: “Recently crowned as the best player in the world, Kevin Sinfield‘s immaculate kicking guided Leeds through the play-offs to Grand Final glory last season, and he has continued that fine form in to this season.
“It is quite apt that he is the first winner of the new monthly award, and he is surely the man to beat for the other goalkickers in Super League for the end of the season award.”
Bradford’s Jamie Foster was the third highest percentage kicker, converting 16 from 18 attempts.
The overall Rhino Super League Top Gun will be presented at the end of season awards dinner, to the player with the best kicking percentage in Super League. It is open to any players who attempt more than 50 goals during the season.