Exhibit 99.1 Certification of Nelson J. Marchioli President and Chief Executive Officer of Denny's Corporation Pursuant to 18 U.S.C. Section 1350, As Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 In connection with Amendment No. 1 of the Annual Report of Denny's Corporation (the "Company") on Form 10-K/A for the year ended December 25, 2002 as filed with the Securities and Exchange Commission on the date hereof (the "Report"), I, Nelson J. Marchioli, President and Chief Executive Officer of the Company, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that: 1) The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and 2) The information contained in the Report fairly presents, in all material respects, the net assets available for benefits and changes in net assets available for benefits of the Plans. /s/ Nelson J. Marchioli - ----------------------- Nelson J. Marchioli President and Chief Executive Officer June 30, 2003 A signed original of this written statement required by Section 906, or other document authenticating, acknowledging, or otherwise adopting the signature that appears in typed form within the electronic version of this written statement required by Section 906, has been provided to Denny's Corporation and will be retained by Denny's Corporation and furnished to the Securities and Exchange Commission or its staff upon request.