This work aimed to unravel the role of Lactobacillus plantarum IFPL935 strain in the colonic metabolism of a polyphenolic red wine extract, when added to a complex human colonic microbiota from the dynamic simulator of the human intestinal microbial ecosystem (SHIME). The concentration of microbial-derived phenolic metabolites and microbial community changes along with fermentative and proteolytic activities were monitored. The results showed that L. plantarum IFPL935 significantly increased the concentration of the initial microbial ring-fission catabolite of catechins and procyanidins, diphenylpropanol, and, similarly, 4-hydroxy-5-(3'-hydroxyphenyl)valeric acid production. Overall, the addition of L. plantarum IFPL935 did not have an impact on the total concentration of phenolic metabolites, except for batches inoculated with colonic microbiota from the effluent compartment (EC), where the figures were significantly higher when L. plantarum IFPL935 was added (24 h). In summary, the data highlighted that L. plantarum IFPL935 may have an impact on the bioavailability of these dietary polyphenols. Some of the microbial-derived metabolites may play a key role in the protective effects that have been linked to a polyphenol-rich diet.