When seeking a job or when employed by a corporation, it is highly recommended to reveal any criminal charges that you may have been convicted of in the past. Typically, when filling out an employment application, the employer will leave a space to reveal any convictions that are found on your personal criminal record. Although it is not technically illegal to withhold information regarding a criminal record, it is highly frowned upon, and often dangerous practice.
The majority of employers will run background checks on their prospective candidates to ensure that they are hiring a law-abiding citizen. If a potential employee fails to reveal their criminal past, and a subsequent background check is run which reveals a criminal record, it is highly unlikely that potential employee will be hired. Legally, the individual is not mandated to reveal their criminal record. However, it is strongly suggested that they do so.
The severity of the crime in which one has been convicted should also be taken into account when alerting an employer about a criminal record. Serious criminal charges should always be revealed to avoid drastic problems that could potentially arise in the future.