To apply for US citizenship, you must establish good moral character prior to your naturalization application. USCIS may look at conduct beyond the one-, three- or five-year period to determine whether you have demonstrated reformed behavior from an earlier period. If you were ever convicted of murder or if you were convicted of an aggravated felony after November 29, 1990, you are permanently barred from naturalization. Contact the knowledgeable immigration attorneys at Spar Bernstein who understand how criminal convictions may affect your naturalization.