To be a mechanical engineer , you must have a bachelor's degree in mechanical engineering. Many employers, however, prefer candidates with a master's or Ph.D. Some companies require that applicants have a license and several professional engineering organizations offer certification programs. You can also pursue professional development by taking an examination to become a Professional Engineer (PE). Upon completion of a certification course, you will be eligible for advancement, which can include supervising teams of engineers and receiving more autonomy in designing.