The fourth and final requirement is that the applicant be a person of good moral character for the five (or three as discussed below) years immediately preceding the filing of the naturalization application. The Immigration and Nationality Act lists certain activities which will prohibit a finding of good moral character. Most of these activities relate to illiegal behavior including, but not limited to: prostitution, illegal gambling, possession of a controlled substance and giving false information to receive an immigration benefit. In addition, the applicant will not be found a person of good moral character if he or she has at any time been convicted of an aggravated felony.
If you are thinking about applying for naturalization, but you have a criminal conviction or pleaded guilty to a crime, you should speak to an immigration lawyer before filing the application.