A full and unconditional state or federal pardon of a crime typically eliminates the grounds for deportation (removal) of a foreign national with lawful permanent resident status (a green card holder) in the United States. In other words, if you've already got a green card and have committed a crime, getting a pardon will save you from deportation.
However, the same does not apply to non-residents of the United States. Despite having been pardoned for a crime, under U.S. immigration laws, the person likely would be inadmissible (ineligible) for any type of visa, whether temporary (nonimmigrant) or permanent (immigrant). Therefore, before you're permitted to legally enter the U.S., you will need to overcome any criminal (or other) grounds of inadmissibility by obtaining a waiver (similar to a pardon) from the U.S. government.
When applying for a temporary visa after a criminal conviction and pardon, you cannot merely fail to mention the crime. Instead, you will need to request a nonimmigrant visa waiver directly from the U.S. embassy or consulate that will process your application. There is no form required for this process.
After filing your application, you will be scheduled for an interview at the U.S. consulate that serves the area where you live. After the interview, the consular officer assigned to your case will decide whether he or she believes a visa should be issued based on the facts, your answers during the interview, and your personal situation as a whole. The decision is completely discretionary (up to the personal judgment of the officer) and will involve consideration of several factors, including:
After weighing all of the factors and considering the crime itself, the consular officer will make a recommendation to the U.S. Department of Homeland Security (DHS). If the officer feels that issuing a visa is not in the best interests of the U.S, your application may be denied.
The fact that you might already have an unexpired visa to the U.S. doesn't mean you can sail through the border. U.S. Customs and Border Protection (CBP) also checks for inadmissibility. You can, however, separately apply for a waiver using USCIS Form I-192.
If you are applying for a visa to live in the U.S. permanently (in other words, a green card), you would request a waiver of inadmissibility by filing USCIS Form I-601, Application for Waiver of Grounds of Inadmissibility.
If you live outside the U.S, you will file the form with the U.S. embassy or consulate abroad. If you live in the U.S. and have applied for your green card through the process known as adjustment of status, you will file the form with USCIS.
One possibility for applying for a waiver is by showing that you have a "qualifying relative" who would suffer extreme hardship if you were denied the visa. A qualifying relative is a U.S. citizen or lawful permanent resident in the U.S. who is also your:
Without a qualifying relative, you do not qualify to apply for this waiver. However, you might still be able to enter the U.S. temporarily through the nonimmigrant visa waiver process above, or by showing rehabilitation, as described below.
The I-601 waiver is often referred to as an "extreme hardship waiver." That means you must convince the U.S. government that if you are not permitted to enter the U.S., your qualifying relative will suffer extreme hardship as a result.
To be considered extreme, the hardship must be more than that which would normally be faced in the typical situation of family separation. You can learn more about proving extreme hardship and the types of hardship that are considered in Showing Extreme Hardship for the I-601 Waiver Process.
The I-601 waiver is also available to a foreign national whose crime took place at least 15 years prior to applying for a visa, based on a showing of rehabilitation. You will also have to show that your receiving the visa will not be contrary to the national welfare, safety, or security of the United States.
Some crimes, by law, cannot be waived at the discretion of an immigration officer or even an immigration judge. Those types are crimes are:
If you have one of these crimes on your record, it won't help to have qualifying relative, nor to show rehabilitation.
Given the complexity involved in successfully obtaining a U.S. visa with a criminal record, even after a pardon, you should absolutely contact an experienced immigration attorney to help you.