Nitrogen (N) is an essential nutrient element in plants that participates in physiological and biochemical regulation. However, the effects of different N applications on cigar tobacco (Nicotiana tabacum L.) growth are not well known. In this study, the differences in agronomical characteristics and nutritional quality of cigar tobacco leaves at the mature and curing stages under different exogenous N applications were explored. The dry matter accumulation of cigar tobacco leaves increased with increasing N application rates. In the two stages, the nutritional quality of cigar tobacco leaves was similar, but the concentrations of N and Cl were increased. To understand the effect of exogenous N on cigar tobacco metabolism, untargeted metabolomics was applied. Six significantly differential metabolites, including phenylalanine, phosphoserine, glutamate, oxoproline, succinylhomoserine, and homoserine, were identified, and the main metabolic pathways around the tricarboxylic acid cycle were identified. These results provide a better understanding of the effects of exogenous N application on the physiological, biochemical, and metabolic processes of cigar tobacco and provide a reference for fertilization control in cigar tobacco production.