The process for immigrants to become naturalized citizens is long and complex, so it is only natural that they be concerned about whether they could be deported if they are convicted of a crime, whether the conviction occurs in California or any other state. While a conviction is not likely to lead to deportation when the crime was committed after the individual became a naturalized citizen, there are some rare cases in which deportation is possible.
Federal law makes it very hard for naturalized citizens to lose their naturalization status. One instance in which this could happen, however, is if they concealed a criminal record during the application process. When the government discovers this criminal past, it has the right to denaturalize the citizen. In the past, most deported and denaturalized citizens were Nazis or other World War II persecutors who did not tell the truth about their past when they applied for citizenship in the United States, but cases like this since then have been very rare.