The victory saw the Blacks leapfrog their opponents and move into sixth place in the table on 20 points, putting them just five behind leaders Glasgow Academicals, but having played a game less.
Berwick opened the scoring on seven minutes when, from a scrum of half way, they broke and Rory Hindhaugh went over for the score, with Jack Webster adding the conversion for a 7-0 lead.
Kirkcaldy were up for the fight, however, and after pressure on the home line they touched down fir a converted try which levelled it up at 7-7.
The game became a strong physical contest, but Berwick regained the initiative when Ben Nicholson scored a second home try, Webster’s conversion making it 14-7, which was the scoreline at the break.
Berwick were playing down the slope in the second half, but it was Kirkcaldy who struck first, an unconverted try bring it back to 14-12.
Ryan Wilson showed a clean pair of heels for a third home try and with Webster adding the extras Berwick stretched their lead to 21-12.
Kirkcaldy continued to pose the Scremerston side a few problems, but Berwick gave themselves some breathing space when James Thompson scored under the posts, securing the bonus point, and with Webster again successful with the boot they moved to 28-12 in front.
Back came the visitors and a converted try made it 29-19, but in the closing stages a line-out led to Thompson going over for his second try of the afternoon, Webster again converting, to complete the scoring.
On Saturday (October 22) Berwick are back in action when they travel to take on Hamilton Bulls, who so far have lost all six games they have played this season.
Meanwhile, Berwick Bears lost 14-10 at home to Sunderland 2nds.
The only score in the first half came from a line-out when Angus Plunkett got an unconverted try, his first for the club, putting them 5-0 up at the break.
Sunderland showed their intent for the second half and they scored two unconverted tries to go 5-14 in front.
But Berwick replied with a good team try through Jack Dalrymple, again unconverted for 10-14.
Berwick then went in search of a winning score, but the visitors held out for the victory.