It would most likely not be a problem; if it has been 10 years or more since the completion of a Driving Under the Influence sentence, a person could be deemed rehabilitated simply as a result of the passage of time. This path would also allow them to stay in Canada. This solution is only possible in cases where someone has a single, non-serious conviction on their record. If you have more than one conviction, you must apply for criminal rehabilitation to clear your criminal record to enter Canada without any issue.
