Surface　charge　transfer　doping　(SCTD)　has　been　established　as　an　efficient　strategy　to　achieve　strong　electronic　coupling　interactions　between　semiconductors　and　dopants,　which　lead　to　highly　efficient　electron　transport　over　semiconductors.　Herein,　we　report　a　facile,　easily　accessible,　and　effective　SCTD　strategy　to　exquisitely　modulate　the　interfacial　charge　transfer　over　transition　metal　chalcogenides　(TMCs:　CdS,　Zn0.5Cd0.5S,　CdIn2S4,　and　ZnIn2S4)　through　surface　modification　with　a　nonconjugated　polymer,　poly(dimethyldiallylammonium　chloride)　(PDDA).　We　provide　evidence　that　PDDA,　as　a　surface　electron　transfer　acceptor,　can　be　used　to　enable　rapid,　directional,　and　tunable　charge　transfer　along　with　an　optimal　charge　lifetime　over　TMCs　in　photoredox　catalysis　because　of　the　high-efficiency　electron-trapping　property　of　quaternary　ammonium　functional　groups　in　the　molecular　structure　of　PDDA.　The　thus-assembled　PDDA-encapsulated　TMC　composite　artificial　photosystems　demonstrate　significantly　enhanced　and　versatile　photoredox　catalytic　activities　toward　visible-light-responsive　photocatalytic　reduction　of　aromatic　nitro　compounds,　photocatalytic　oxidation　of　aromatic　alcohols,　and　photocatalytic　H2　production,　wherein　the　ultrathin　PDDA　layer　accelerates　the　interfacial　charge　transport　and　separation　rate　over　TMC　substrates.　Moreover,　it　was　evidenced　that　such　an　interface　engineering　strategy　is　general　for　a　collection　of　TMCs.　Our　work　will　provide　conceptual　insights　into　nonconjugated　polymer-based　artificial　photosystems　for　optimizing　solar　energy　utilization.　©　2024　American　Chemical　Society.