Persons convicted of a crime may "appeal" their cases, requesting that a higher court to review certain aspects of the case for legal error, as to either the conviction itself or the sentence imposed. In an appeal, the defendant, now called the appellant, argues that, based on key legal mistakes which impacted the jury's decision and/or the sentence imposed, the case should be dismissed or the appellant should be re-tried or re-sentenced.
In considering an appeal, the court reviewing the case looks only at the record of the proceedings in the lower court, and does not consider any new evidence. The record is made up of the court reporter's transcripts of everything said in court, whether by the judge, the attorneys, or witnesses. Anything else admitted into evidence, such as documents or objects, also becomes part of the record.
In reaching a decision on the appeal, the higher court, also called the appellate court, looks to this record and to the written "briefs" filed by both sides of the appeal. For example, an appellant challenging a conviction or sentence files an opening brief, arguing how and why the conviction or sentence was legally wrong. In turn, the government files its own brief to illustrate why the conviction or sentence should be upheld. The appellant typically has an opportunity to file a second brief in response to the government's position, and the appellate court may hear oral arguments from each side before reaching a decision on the appeal.
At both the state and federal court levels, there are a variety of options for obtaining relief after a criminal conviction or sentence. It is important to note that, although it may take a number of months for an appeal to be heard and decided, most states require an appellant to notify the courts and the government of the intent to appeal very soon after a conviction or sentence.