<PAGE>
Exhibit 24
POWER OF ATTORNEY
KNOW ALL MEN BY THESE PRESENTS, that each person whose signature appears
below constitutes and appoints James Dimon, Verne G. Istock, William P.
Boardman, Charles W. Scharf, Christine A. Edwards, M. Eileen Kennedy, James L.
Foorman and Laurence Goldman, jointly and severally, his attorney-in-fact, each
with power of substitution, for him in any and all capacities to sign one or
more Registration Statements on Form S-3 (or, if deemed appropriate by the
General Counsel of this Corporation, Form S-4) relating to securities
(including, but not limited to, preferred securities and debt securities) to be
issued or guaranteed by BANK ONE CORPORATION (the "Corporation") and any
amendments thereto (including any post-effective amendments) and any subsequent
registration statement filed by the Corporation pursuant to Rule 462(b) of the
Securities Act of 1933 with respect to such Securities, in either case pursuant
to resolutions adopted by the Board of Directors of the Corporation on July 18,
2000, and to file the same, with exhibits thereto, and other documents in
connection therewith, with the Securities and Exchange Commission hereby
ratifying and confirming all that each of said attorneys-in-fact, or his
substitute or substitutes, may do or cause to be done by virtue hereof.
Signature Title
--------- -----
/s/ William P. Boardman Director
-----------------------
William P. Boardman
/s/ John H. Bryan Director
-----------------------
John H. Bryan
Director
-----------------------
Siegfried Buschmann
/s/ James S. Crown Director
-----------------------
James S. Crown
/s/ James Dimon Principal Executive Officer and Director
-----------------------
James Dimon
/s/ Bennett Dorrance Director
-----------------------
Bennett Dorrance
/s/ Dr. Maureen A. Fay, O.P. Director
-----------------------
Dr. Maureen A. Fay, O.P.
/s/ John R. Hall Director
-----------------------
John R. Hall
<PAGE>
/s/ Verne G. Istock Director
-----------------------
Verne G. Istock
/s/ Laban P. Jackson, Jr. Director
-----------------------
Laban P. Jackson, Jr.
/s/ John W. Kessler Director
-----------------------
John W. Kessler
/s/ Richard A. Manoogian Director
-----------------------
Richard A. Manoogian
/s/ William T. McCormick Director
-----------------------
William T. McCormick
/s/ Thomas E. Reilly, Jr. Director
-----------------------
Thomas E. Reilly, Jr.
/s/ John W. Rogers, Jr. Director
-----------------------
John W. Rogers, Jr.
Director
-----------------------
Thekla R. Shackelford
/s/ Alex Shumate Director
-----------------------
Alex Shumate
/s/ Frederick P. Stratton, Jr. Director
-----------------------
Frederick P. Stratton, Jr.
/s/ Robert D. Walter Director
-----------------------
Robert D. Walter
<PAGE>
/s/ Charles W. Scharf
-----------------------
Charles W. Scharf Principal Financial Officer
Dated: July 18, 2000
<PAGE>
POWER OF ATTORNEY
KNOW ALL MEN BY THESE PRESENTS, that each person whose signature appears
below constitutes and appoints James Dimon, William P. Boardman, Charles W.
Scharf, Christine A. Edwards, M. Eileen Kennedy, James L. Foorman and Laurence
Goldman, jointly and severally, his attorney-in-fact, each with power of
substitution, for him in any and all capacities to sign one or more Registration
Statements on Form S-3 (or, if deemed appropriate by the General Counsel of this
Corporation, Form S-4) relating to securities (including, but not limited to,
preferred securities and debt securities) to be issued or guaranteed by BANK ONE
CORPORATION (the "Corporation") and any amendments thereto (including any
post-effective amendments) and any subsequent registration statement filed by
the Corporation pursuant to Rule 462(b) of the Securities Act of 1933 with
respect to such Securities, in either case pursuant to resolutions adopted by
the Board of Directors of the Corporation on July 18, 2000, and to file the
same, with exhibits thereto, and other documents in connection therewith, with
the Securities and Exchange Commission hereby ratifying and confirming all that
each of said attorneys-in-fact, or his substitute or substitutes, may do or
cause to be done by virtue hereof.
/s/ William J. Roberts Principal Accounting Officer
-----------------------
William J. Roberts
September 22, 2000
