Half-centuries for Sean Dickson, Darren Stevens and Wayne Parnell helped Kent gain three bonus points as Sussex paceman Jofra Archer grabbed seven wickets on day one of the Specsavers County Championship match at Hove.
Sam Northeast won the toss and opted to bat under cloudy skies at the seaside with Sean Dickson hitting his seventh 50 in his 25th County Championship innings.
Matt Coles struck shortly before stumps to leave the hosts on 11-1 in reply to Kent's 304 all out.
Barbados-born Archer was the pick of the home attack and removed both openers. At the other end, Ajmal Shahzad picked up three wickets as a 123-run stand between Stevens and the returning Parnell pushed Kent in bonus point territory.
Bell-Drummond, Denly (who passed 9,000 first class career runs) and Rouse were bowled without playing a shot as the seamers extracted movement through the air and off the pitch.
Dickson batted patiently to see off the new ball and score eight fours and a six in his 179-ball stay before nicking behind to Sussex gloveman Ben Brown.
Northeast and Gidman were caught at mid-on as shot-making proved difficult before Kent recovered from to 152 for six to post 304.
Stevens struck 11 fours and a six in his 72nd first-class 50 before Parnell repeated the feat off 88 balls to record his eleventh red-ball half-century.
Archer returned to take the new ball and clean up the tail as Sussex’s South African international debutants Vernon Philander and Stiaan van Zyl finished wicketless.
At stumps, the hosts reached 11-1 after facing six testing overs from Matt Coles and Parnell. Coles trapped veteran opener Chris Nash LBW.