Štefulj spent his youth years with Međimurje, Varaždin and NK Zagreb. He started his senior career with NK Zagreb in 2017. In February 2018, he was signed by Rijeka of the Croatian top division. Rijeka loaned Štefulj to Krško in 2018, and then to Varaždin in 2019. In January 2020, he returned to Rijeka.
