Source-to-sink partitioning in potato is a critical process during the growing season for development of tubers and reaching high yields. Potato tuber yields depend on nitrogen (N) supply. The relationship between source-to-sink partitioning and N supply was examined in the study. Gene expression in responses to N supply was examined in leaves of plants grown in the same field plots used to quantify yield. A single field trial was used initially to identify a set of 63 N responsive genes using transcriptome sequencing. Expression of these 63 genes were further examined in seven field trials with varying N rates, sites, and cultivars using the Nanostring nCounter platform. Least absolute shrinkage and selection operator (LASSO) regression models of gene expression predictive of yield, total plant N uptake, and tuber-specific gravity (proxy for dry matter) were built. Genes in the LASSO model for yield were associated with source–sink partitioning. A key gene regulating tuberization and senescence, StSP6A Flowering locus T, was found in the LASSO model predicting tuber yield, but not the other models. An aminotransferase involved in photorespiratory N assimilation and amino acid biosynthesis was found in all LASSO models. Other genes functioning in amino acid biosynthesis and integration of sulfur (S) and N metabolism were also found in the yield prediction model. The study provides insights on N responses in foliage of potato plants that affect source–sink partitioning. Additionally, N-responsive genes predictive of yield are candidate indicators of monitoring crop N status and tolerance to N stress in breeding.