The technical stuff. For each bankruptcy petition that is filed, the United States Trustee automatically and randomly appoints a disinterested person (member of a panel of Chapter 7 trustees or "panel trustee") to serve as an interim trustee. The interim trustee serves until a permanent trustee is elected or designated at the 341(a) hearing. In almost every case, the interim trustee will continue to serve as the permanent trustee.
In simple English please? A panel trustee is appointed in each Chapter 7 case to review the bankruptcy petition and schedules filed with the Court and to determine if the debtor has any non-exempt assets available for distribution to creditors. The panel trustee is required to be independent and works primarily for the benefit of the debtor's unsecured creditors.
And who is this person exactly? Chapter 7 trustees are not government employees. They are private citizens appointed and supervised by the Office of the U.S. Trustee (a division of the U.S. Department of Justice) to administer bankruptcy cases under chapter 7 of the U.S. Bankruptcy Code. Many chapter 7 trustees are also attorneys or accountants who continue to practice their profession after appointment to the panel.
So how does this all play out? In short, the trustee is then person that will be asking you questions during your 341(a) hearing. Make sure you answer the questions truthfully and to the best of your knowledge. If he/she asks for any additional documents, make sure you provide them as soon as possible. If you have non-exempt assets, the trustee may take action to pursue them (i.e.: liquidate them) for the benefit of your creditors.