Trustee is the term used for several different roles in the bankruptcy process. This is the person who administers Chapter 7 cases. He is essentially a representative for the creditors as a body. He is appointed by the United States Trustee , an officer of the Department of Justice, who oversees his performance. He is not himself a government employee.
Trustees are frequently lawyers or accountants.
The trustee can file objections to claims of exemption or oppose the debtor's discharge, but he doesn't decide those questions. The judge decides disputed questions. Trustees are paid in part from the filing fee paid to the court at the commencement of the case. Any compensation they receive above that is a fee based on the money they handle as part of the estate. He also serves as the disbursing agent for payments made by the debtor into the plan.