Departing from common methods of employing magnetic materials, generation of spin-polarized electrons in a semiconductor mediated by spin-dependent processes via defects represents an unconventional approach without invoking magnetism. Here, we provide a brief description of the physical principle and review our recent work on exploring this unconventional approach to achieve desired spin functionalities in nonmagnetic semiconductors without requiring a magnetic layer or an external magnetic field. We demonstrate that fundamental spin functionalities such as spin filtering, spin amplification and spin detection can be achieved at room temperature (RT). By combining the spin-filtering effect and electron–nuclear spin interaction, we also show that efficient nuclear spin hyperpolarization of a defect atom in a semiconductor can be realized at RT via spin-polarized conduction electrons. Such approaches could potentially lead to development of basic spintronic components that serve as building blocks in future spintronics and spin-photonics, thereby providing an attractive solution to the current and important problems in room-temperature spin-functional semiconductors.