Acute respiratory viral infections are a major global health burden, studying them across diverse regions is vital for tracking spread and spotting disease trends. Using metagenomic next-generation sequencing (mNGS), we analyzed 250 respiratory samples and 195 blood samples collected during winter 2023 from Jilin Province, northeast China, to identify causative agents of respiratory infections. Viral enrichment yielded 399,256 viral sequence reads. Severe Acute Respiratory Syndrome Coronavirus 2 (lineage BA.2), human respiratory syncytial virus B (lineage GB5.0.5a), and influenza B virus (lineage V1A.3a.2) were identified as conservative respiratory pathogens across both pediatric and adult populations. Influenza A virus (lineage 3c.2a1b.2a), rhinovirus (subtype C), human respiratory syncytial virus A (lineage GA2.3.5), human respiratory syncytial virus B (lineage GB5.0.5a), and human metapneumovirus (lineage A2c) were detected in pediatric or adult respiratory samples. Strikingly, Human Pegivirus (genotype 3) was detected exclusively in adult blood samples. Comprehensive phylogenetic analyses were performed for representative viruses. Notably, a novel picobirnavirus was identified in adult sputum samples, exhibiting >90% nucleotide and >70% amino acid similarity to reference sequences. This finding was validated by nested RT-PCR, representing the first documented detection of picobirnavirus in respiratory specimens from China. Collectively, these findings delineate the winter 2023 respiratory viruses of Northeast China, informing region-specific surveillance to mitigate future public health risks.