He may be more precisely titled after the (type of) court, e.g. clerk of the peace attending to a justice of the peace, clerk of the police court, etc. On Guernsey, the medieval French term Grieffe is used (in the magistrate's court).
In courts without a clerk, or if there is no specific officer otherwise available, the judge may have authority to act as clerk of the court, as sometimes in a short-staffed probate court.
In the United States federal courts, each district court, court of appeals, and bankruptcy court, as well as the Supreme Court, has its own clerk, appointed by the judges of the court. The clerk is the custodian of the court's records and also has responsibility for collecting fees and other deposits of money made with the court. The court clerk is not to be confused with the law clerk who assists the judge in making legal determinations. And in the courts within the City of New York, the Court Clerk, who is a Peace Officer, is the highest ranking, non-judicial person in the courtroom. The Court Clerk is the supervisor of the Court Officers in the Courtroom.
In an English Magistrates' Court, where the judges will usually have no legal qualifications, the Court Clerk will be legally qualified. The magistrates decide on the facts at issue; the clerk advises them on the law relating to the case.