When you interview for a position that has requirements below your skill set and knowledge base, you run the risk of being deemed overqualified for the position. No employer wants to go through multiple hiring processes because an employee left for a better position after a short time. Take the interview as an opportunity to present yourself in the best light, and to do this, prepare yourself to have an answer ready to the "You're overqualified" statement.
Formulate an answer before you ever set foot in the interview room. Consider your reasons why you want to take a position that is below your level of qualifications. If you cannot answer this question for yourself before the interview, you cannot answer it well during the interview. Perhaps you have been out of the workforce for several years and feel as if you need to regain your skills. Or maybe you realize you prefer a more hands-on approach to your job rather than a managerial one. If you don't fully understand your reasons for wanting a job below your skill set, you risk accepting a position you might end up hating later.
Address the assertion that you are overqualified by giving convincing answers. The answers you give the interviewer, however, might be different than your own personal reasons. While you might be desperate for a job, never tell a potential employer that; otherwise, you will not get it. If you were a manager at your former job, say that you don't see this position as below you. Rather, you see it as an opportunity to go back to your roots and to do the kind of job you prefer, rather than delegating. If you were a stay-at-home-parent for several years, you might tell the interviewer that you want an opportunity to gain new skills and work your way up rather than starting where you left off. Regardless of your true reason for wanting the job, it is important to appear sincere and willing to work.
Ask questions, instead of waiting for the interviewer to question you. This shows you have a keen interest in the job without appearing desperate. Questions such as, "What are the most important job functions?" and "What traits are important in the person who fills this job?" will help quell the over-qualification stigma by addressing the issue head-on. Other questions you might ask are "What are your expectations of the person who fills this position six months and one year down the road?" These questions allow you formulate a reply to the over-qualified statement if it does come up. This also keeps you from talking yourself out of a job. The more you talk discuss your overwhelming qualifications, the less chance you might have of getting the job.
Counter the question, "Why should I think you'll stay with the company?" with direct responses. A smart interviewer may try to challenge you more than once regarding the over-qualification topic. If you were at your last position for a significant amount of time, point that out. Emphasize that you are not a quitter and that your biggest motivation is assimilating into the company's culture. Discuss your future with the company in terms of being a partner in the company's success, rather than what the company can do for you. Assure the interviewer that you will not get bored with the work by expressing enthusiasm for the company and its mission.