Character witnesses can testify on behalf of another as to that person's positive or negative character traits and the person's reputation in the community. Such character evidence is often used in criminal cases. Its usage is limited in civil cases. The testimony has to be within the scope of a federal rule of evidence or state rule of evidence.
Testifying for the defendant:
Under common law, the defendant is allowed to call character witnesses to testify for his or her character. Character witnesses can only testify for the defendant by introducing testimony about the defendant’s reputation or by relevant instances of the defendant’s conduct. The government can then cross-examine that witness regarding his/her knowledge of specific instances of the defendant's misconduct in order to help the jury evaluate the quality of the character testimony.
A majority of courts hold that the prosecution may not cross-examine a defendant's character witness by asking whether his or her opinion of the defendant would change if the defendant were guilty of the crime. The prosecution also may not ask whether the witness is aware that the defendant is guilty.
The character witness must show some acquaintance or direct contact with the defendant. Federal courts do not have any minimum period of acquaintance for the character witness to testify for the defendant. (See U.S. v. Haimowitz).
Testifying for or against other witnesses:
A character witness can also testify as to his favorable/unfavorable opinion or the good/bad reputation of other witnesses for truth and veracity. A character witness can do so during direct examination or when being cross-examined.
[Last updated in May of 2020 by the Wex Definitions Team]