The category under which a crime is classified can make a difference in both substantive and procedural criminal law. Substantive criminal law defines the elements of many crimes in reference to whether they were committed in furtherance of a felony. Burglary, for example, requires proof that the defendant broke into another person's dwelling with the intent to commit a felony. If a defendant convinces a jury that he only had the intent to steal a misdemeanor's worth of property after breaking into the victim's home, the jury cannot return a conviction for burglary.

The substantive consequences for being convicted of a felony are also more far reaching than the consequences for other types of crimes. One convicted of a felony is disqualified from holding public office in many jurisdictions. Felons may also lose their right to vote or serve on a jury. In several states attorneys convicted of a felony lose their right to practice law. Misdemeanants with no felony record rarely face such serious consequences.

Criminal procedure sets forth different rules that govern courts, defendants, and law enforcement agents depending on the level of offense charged. The Fourth Amendment to the U. S Constitution allows police officers to make warrantless arrests of suspected felons in public areas so long as the arresting officer possesses probable cause that the suspect committed the crime. Officers may make warrantless arrests of suspected misdemeanants only if the crime is committed in the officer's presence. Police officers do not have the authority to shoot an alleged misdemeanant while attempting to make an arrest, unless the shots are fired in self-defense. Officers generally have more authority to use deadly force when effectuating the arrest of a felon.

Most criminal courts have limited jurisdiction over the kinds of cases they can hear. A court with jurisdiction over only misdemeanors has no power to try a defendant charged with a felony. Defendants may be charged by information (i.e., a formal written instrument setting forth the criminal accusations against a defendant) when they are accused of a misdemeanor, whereas many jurisdictions require that defendants be charged by a grand jury when they are accused of a felony.