| Name | | Appointed | Presented credentials | End of term |
| John R. Carter | | June 24, 1910 | | |
| John Brinkerhoff Jackson | | August 12, 1911 | February 1, 1912 | Presented recall, October 18, 1913 |
| Charles J. Vopicka | Non-career appointee | September 11, 1913 | December 26, 1913 | Relieved of active functions pertaining to Legation Sofia, December 17, 1918 |
| Charles S. Wilson | Foreign Service officer | October 8, 1921 | December 5, 1921 | Presented recall, October 4, 1928 |
| H. F. Arthur Schoenfeld | Foreign Service officer | July 17, 1928 | | |
| Henry Wharton Shoemaker | Non-career appointee | January 22, 1930 | March 28, 1930 | Left post, August 2, 1933 |
| Frederick A. Sterling | Foreign Service officer | September 1, 1933 | April 3, 1934 | Left post, June 30, 1936 |
| Ray Atherton | Foreign Service officer | July 13, 1937 | October 21, 1937 | Left post, July 5, 1939 |
| George H. Earle III | Non-career appointee | February 14, 1940 | April 2, 1940 | Bulgaria declared war on the U.S., December 13, 1941 |
| Donald R. Heath | Foreign Service officer | September 30, 1947 | November 8, 1947 | Declared persona non grata by Government of Bulgaria, January 19, 1950 |
| Edward Page, Jr. | Foreign Service officer | November 23, 1959 | March 14, 1960 | Left post, May 25, 1962 |
| Eugenie Anderson | Non-career appointee | May 28, 1962 | August 3, 1962 | Left post, December 6, 1964 |
| Nathaniel Davis | Foreign Service officer | May 6, 1965 | June 4, 1965 | Left post, May 20, 1966 |
| John M. McSweeney | Foreign Service officer | September 16, 1966 | October 26, 1966 | Promoted to Ambassador Extraordinary and Plenipotentiary |
| Name | | Appointed | Presented credentials | End of term |
| John M. McSweeney | Foreign Service officer | April 5, 1967 | April 19, 1967 | Left post, May 29, 1970 |
| Horace G. Torbert, Jr. | Foreign Service officer | October 6, 1970 | November 4, 1970 | Left post, January 23, 1973 |
| Martin F. Herz | Foreign Service officer | February 28, 1974 | April 3, 1974 | Left post, August 6, 1977 |
| Raymond L. Garthoff | Foreign Service officer | July 29, 1977 | September 16, 1977 | Left post, October 9, 1979 |
| Jack Richard Perry | Foreign Service officer | September 20, 1979 | October 17, 1979 | Left post, September 27, 1981 |
| Robert L. Barry | Foreign Service officer | November 25, 1981 | December 8, 1981 | July 12, 1984 |
| Melvyn Levitsky | Foreign Service officer | September 21, 1984 | November 13, 1984 | Left post, February 6, 1987 |
| Sol Polansky | Foreign Service officer | June 15, 1987 | September 4, 1987 | Left post, August 17, 1990 |
| Hugh Kenneth Hill | Foreign Service officer | August 6, 1990 | September 18, 1990 | Left post, September 5, 1993 |
| William Dale Montgomery | Foreign Service officer | October 8, 1993 | October 27, 1993 | Left post, January 17, 1996 |
| Avis T. Bohlen | Foreign Service officer | July 2, 1996 | September 5, 1996 | Left post August 13, 1999 |
| Richard Monroe Miles | Foreign Service officer | August 9, 1999 | September 8, 1999 | Left post February 28, 2002 |
| James W. Pardew | Foreign Service officer | April 1, 2002 | May 13, 2002 | Left post, July 30, 2005 |
| John Beyrle | Foreign Service officer | July 9, 2005 | September 8, 2005 | April 28, 2008 |
| Nancy McEldowney | Career foreign service officer | May 2, 2008 | August 26, 2008 | July 30, 2009 |
| James B. Warlick, Jr. | Career foreign service officer | December 24, 2009 | January 19, 2010 | September 14, 2012 |
| Marcie Berman Ries | Career foreign service officer | May 24, 2012 | October 1, 2012 | July 28, 2015 |
| Eric S. Rubin | Career foreign service officer | December 9, 2015 | January 27, 2016 | July 9, 2019 |
| Herro Mustafa | Career foreign service officer | September 29, 2019 | October 18, 2019 | Incumbent |
