By using ab initio calculations, we explored the electronic and magnetic properties of 3d transition metals (TM = V, Cr, Mn, Fe, Co, Ni, and Cu)-doped SrTiO3 (STO) systems. The stability of doped systems is analyzed by computing their formation energies, which exhibits a strong interdependence on the dopants atomic numbers. Our results show that the versatile electronic and magnetic properties can be obtained by TM-doping, which are ranging from ferromagnetic half-metal (V-, Cr-, and Fe-doped systems), magnetic/non-magnetic semiconductors (Mn-, Co-/Ni-doped systems), and magnetic metal (Cu-doped system). From total and orbital resolved partial density of states, it is found that 3d orbitals of dopant atoms are playing the key role in Cunning the physical properties of the STO. The induced magnetism in these doped systems is explained by comparing the valence electronic configurations of host (Ti) and doped (TM) atoms. Our findings may trigger further experimental researches to obtain stable magnetic properties in TM-doped STO systems.