Nuclear ubiquitous casein and cyclin-dependent kinase substrate 1 (NUCKS1) is highly expressed in a variety of malignant tumors and functions as an oncogene; however, its role in colorectal cancer (CRC) remains unclear. We aimed to explore the function and regulatory mechanisms of NUCKS1 and potential therapeutic agents targeting NUCKS1 in CRC. We knocked down and overexpressed NUCKS1 in CRC cells and explored its effects in vitro and in vivo. Flow cytometry, CCK-8, Western blotting, colony formation, immunohistochemistry, in vivo tumorigenic, and transmission electron microscopy analyses were performed to determine the effects of NUCKS1 on CRC cell function. LY294002 was used to examine the mechanism of NUCKS1 expression in CRC cells. Potential therapeutic agents for NUCKS1-high CRC patients were analyzed using the CTRP and PRISM datasets, and the function of selected agents was determined by CCK-8 and Western blotting. We revealed that NUCKS1 was highly expressed in CRC tissues and clinically correlated with poor prognosis in CRC patients. NUCKS1 knockdown induces cell cycle arrest, inhibits CRC cell proliferation, and promotes apoptosis and autophagy. These results were reversed when NUCKS1 was overexpressed. Mechanistically, NUCKS1 exerts a cancer-promoting function by activating the PI3K/AKT/mTOR signaling pathway. This was reversed when LY294002 was used to inhibit the PI3K/AKT pathway. Furthermore, we determined that mitoxantrone exhibited high drug sensitivity in NUCKS1-overexpressing CRC cells. This work demonstrated NUCKS1 plays a crucial role in CRC progression via the PI3K/AKT/mTOR signaling pathway. Additionally, mitoxantrone may be a potential therapeutic agent for CRC treatment. Therefore, NUCKS1 represents a promising anti-tumor therapeutic target.