Protein arginine methyltransferase 1 (PRMT1) catalyzing the formation of asymmetric dimethylarginines has been implicated in cancer development, metastasis, and prognosis. In this study, we investigated the effects of low PRMT1 levels on a non-MYCN amplified neuroblastoma SK-N-SH cell line. Stable PRMT1-knockdown (PRMT1-KD) cells showed reduced growth rates and cell cycle arrest at G2/M. They also exhibited senescent phenotypes and increased p53 expression. p21 and PAI-1, which are two p53 downstream targets critical for senescence, were significantly induced in SK-N-SH cells subjected to either PRMT1-KD or inhibitor treatment. The induction was suppressed by a p53 inhibitor and marginal in a p53-null SK-N-AS cell line, suggesting dependence on p53. In general, the DNA damage and ROS levels of the PRMT1-KD SK-N-SH cells were slightly increased. Their migration activity also increased with the induction of PAI-1. Thus, PRMT1 downregulation released the repression of cellular senescence and migration activity in SK-N-SH cells. These results might partially explain the poor prognostic outcome of low PRMT1 in a non-MYCN-amplified cohort and indicate the multifaceted complexity of PRMT1 as a biological regulator of neuroblastoma.