The position of Assistant Secretary for Hydrocarbons and Geothermal Energy Office (HGEO) is a Presidentially-appointed position. In most cases, it requires that a candidate nominated by the President be confirmed by the U.S. Senate. The following Presidential appointees have served as Assistant Secretary since the position was established. Others have served in acting capacities during the absence of a Presidentially-appointed official.
Chronological List of Assistant Secretaries for Hydrocarbons and Geothermal Energy Office
On July 4, 2021, the Office of Fossil Energy (FE) officially added “Carbon Management” to its name to become the Office of Fossil Energy and Carbon Management (FECM).
On November 20, 2025, the Office was officially rebranded as the Hydrocarbons and Geothermal Energy Office (HGEO).
The following individuals have served as Assistant Secretary since the position was established. Those who served with Presidential appointments are shown in bold; those who served in an acting capacity are shown with an asterisk (*). This list reflects the continuity of leadership from the former FE and FECM to the present-day HGEO.
| ASSISTANT SECRETARY | TERM SERVED |
| George Fumich, Jr.* | October 1979 – January 1980 |
| George Fumich, Jr. | January 1980 – January 1981 |
| George Fumich, Jr.* | January 1981 – March 1981 |
| Roger W.A. Legassie* | April 1981 – August 1981 |
| Jan W. Mares | August 1981 – January 1984 |
| William A. Vaughan | January 1984 –June 1985 |
| Donald L. Bauer* | June 1985 – October 1986 |
| J. Allen Wampler | October 1986 – July 1989 |
| Michael R. McElwrath* | July 1989 – February 1990 |
| Robert H. Gentile | February 1990 – June 1991 |
| Linda G. Stuntz* | June 1991 – November 1991 |
| James G. Randolph | November 1991 – January 1993 |
| Jack Siegel* | January 1993 – July 1994 |
| Patricia Fry Godley | July 1994 – July 1998 |
| Robert S. Kripowicz* | August 1998 – April 1999 |
| Robert W. Gee | April 1999 – September 2000 |
| Robert S. Kripowicz* | September 2000 – February 2002 |
| Carl Michael Smith | February 2002 – March 2004 |
| Mark R. Maddox* | March 2004 – January 2006 |
| Jeffrey D. Jarrett | January 2006 – March 2007 |
| Thomas D. Shope* | March 2007 – October 2007 |
| James A. Slutz* | July 2008 – January 2009 |
| Vic Der* | January 2009 – August 2009 |
| James Markowsky | August 2009 – November 2010 |
| Vic Der* | November 2010 – April 2011 |
| Charles McConnell | March 2012 – February 2013 |
| Christopher A. Smith* | February 2013 – December 2014 |
| Christopher A. Smith | December 2014 – January 2017 |
| Doug Hollett* | January 2017 – September 2017 |
| Mark Maddox* | September 2017 – November 2017 |
| Steven E. Winberg | November 2017 – January 2021 |
| Jennifer Wilcox* | January 2021 - May 2022 |
| Brad Crabtree | May 2022 - January 2025 |
| Tala Goudarzi* | March 2025 – September 2025 |
| Kyle Haustveit | September 2025 - |
Last Updated: March 30, 2026