Background: Nutrient profiling systems could be useful public health tools as a basis for front-of-package nutrition labeling, advertising regulations, or food taxes. However, their ability beyond characterization of foods to adequately characterize individual diets necessitates further investigation. Objectives: The objectives of this study were 1) to calculate a score at the individual level based on the British Food Standard Agency (FSA) food-level nutrient profiling system of each food consumed, and 2) to evaluate the validity of the resulting diet-quality score against food group consumption, nutrient intake, and sociodemographic and lifestyle variables. Methods: A representative sample of the French population was selected from the NutriNet-Sante Study (n = 4225). Dietary data were collected through repeated 24-h dietary records. Sociodemographic and lifestyle data were self-reported. All foods consumed were characterized by their FSA nutrient profile, and the energy intake from each food consumed was used to compute FSA-derived aggregated scores at the individual level. A score of adherence to French nutritional recommendations [Programme National Nutrition Sante guideline score (PNNS-GS)] was computed as a comparison diet-quality score. Associations between food consumption, nutritional indicators, lifestyle and sociodemographic variables, and quartiles of aggregated scores were investigated using ANOVAs and linear regression models. Results: Participants with more favorable scores consumed higher amounts of fruits [difference Delta = 156 g/d between quartile 1 (less favorable) and quartile 4 (most favorable), P < 0.001], vegetables (Delta = 85 g/d, P < 0.001), and fish, and lower amounts of snack foods (Delta = -72 g/d, P < 0.001 for sugary snacks); they also had higher vitamin and mineral intakes and lower intakes of saturated fat. Participants with more favorable scores also had a higher adherence to nutritional recommendations measured with the PNNS-GS (Delta = 2.13 points, P < 0.001). Women, older subjects, and higher-income subjects were more likely to have more favorable scores. Conclusion: Our results show adequate validity of the FSA nutrient profiling system to characterize individual diets in a French context. The NutriNet-Sante Study was registered in the European Clinical Trials Database (EudraCT) as 2013-000929-31.