Can a Corporation File a Federal Lawsuit Pro Se?
Only people can appear pro se. A corporation is not a "person" for this purpose. In other words, a person who is not an attorney may represent himself or herself, but may not represent a corporation, even if the person is the sole owner of the corporation. The corporation must be represented by a lawyer. You may appear in court with the lawyer for the corporation, but only the lawyer can "speak" for the corporation in court.
The United States Supreme Court has prohibited any artificial entity from being represented by persons who are not licensed attorneys. See, e.g., Rowland v. California Men's Colony, 506 U.S. 194, 201-03 (1993) (citing cases dating from 1824 forward holding that a corporation may only be represented by licensed counsel).
As the courts have recognized, the rationale for that rule applies equally to all artificial entities. Thus, save in a few aberrant cases, the lower courts have uniformly held that 28 U.S.C. § 1654, providing that "parties may plead and conduct their own cases personally or by counsel," does not allow corporations, partnerships, or associations to appear in federal court otherwise than through a licensed attorney.
Please see the following federal statute:
§ 1654. Appearance personally or by counsel
In all courts of the United States the parties may plead and conduct their own cases personally or by counsel as, by the rules of such courts, respectively, are permitted to manage and conduct causes therein.