It's hard to define "sacked" in this context, since if you want to fire someone you could just as easily "ask" them to resign. There are also a couple of instances of people being offered a "promotion" to an ambassadorship, which also would conveniently remove them from the local political scene. Below is an entire (to date) list of U.S. Secretaries of State and my interpreted reasons for why they left their posts. This information was mostly gleaned from their associated Wikipedia pages.
By my count there are 4 instances of outright "sacking" highlighted in bold below(Timothy Pickering, Edward Livingston, James G. Blaine, and Rex Tillerson). Some others, such as Edmund Randolph and Robert Lansing, are not quite as clear cut.
- Thomas Jefferson - Resigned to focus on rallying support against the influence of Alexander Hamilton and John Jay.
- Edmund Randolph - Resigned following a scandal after the British intercepted a French message containing information Randolph shared but shouldn't have.
- Timothy Pickering - Dismissed by John Adams after quarreling over John Adams' attempt to make peace with France during the Quasi-War.
- John Marshall - Served through the end of Adams' term, later appointed to Supreme Court.
- James Madison - Served throughout Jefferson's terms, later elected President.
- Robert Smith - Resigned, though after refusing the "promotion" of Ambassador to Russia and publicly criticizing President Madison.
- James Monroe - Resigned two months after the British burned the U.S. Capitol and the White House. He was serving a dual role at the time as also the U.S. Secretary of War, and after his resignation there was no immediate successor appointed so he was the de facto Secretary of State for another six months. Later elected President.
- John Quincy Adams - Served throughout Monroe's two terms, later elected President.
- Henry Clay - Served throughout J.Q. Adams' term.
- Martin Van Buren - Resigned following a split in Andrew Jackson's cabinet, the Petticoat Affair
- Edward Livingston - Replaced with Louis McLane by President Jackson in a Cabinet shakeup and attempt to undermine the creation of the Second Bank of the United States.
- Louis McLane - Resigned after being undermined by Martin Van Buren in negotiating with the French.
- John Forsyth - Served the remainder of Jackson's administration and the entirety of Martin Van Buren's term. Died 7 months after leaving office.
- Daniel Webster - Resigned All Whigs under President John Tyler resigned their cabinet positions while he was in Europe, and he ultimately acceeded to their pressure to also resign.
- Abel Upshur - Died in Office aboard the USS Princeton when a ceremonial firing of her guns caused the gun to burst, spraying shrapnel into the crowd.
- John C. Calhoun - Served the remainder of President Tyler's term. Later he was elected Senator from South Carolina. Earlier he was Vice President under both John Q. Adams and Andrew Jackson.
- James Buchanan - Served throughout President Polk's term. Later elected President.
- John M. Clayton - Resigned after President Taylor's death.
- Daniel Webster - Died in Office after being appointed by President Fillmore. He fell from a horse and suffered a crush to the head, complicated by cirrhosis of the liver. This is the same person as #14.
- Edward Everett - Resigned under pressure from abolitionists and failing health during the debate over the Kansas-Nebraska act.
- William L. Marcy - Served throughout President Pierce's term.
- Lewis Cass - Resigned over disagreements with President Buchanan's disposition of federal forces in the south.
- Jeremiah S. Black - Served through the remainder of President Buchanan's term.
- William H. Seward - Served throughout President Lincoln's terms.
- Elihu B. Washburne - Resigned after 11 days due to illness.
- Hamilton Fish - Served throughout President Grant's terms.
- William M. Evarts - Served throughout President Hayes' term.
- James G. Blaine - Resigned under extreme pressure after President Garfield was assassinated and President Arthur's stalwarts assumed power.
- Frederick T. Frelinghuysen - Served the remainder of Garfield's term.
- Thomas F. Bayard - Served throughout President Cleveland's term.
- James G. Blaine - Resigned due to failing health. This is the same person as #28.
- John W. Foster - Served through the remainder of President Harrison's term.
- Walter Q. Gresham - Died in Office.
- Richard Olney - Served through the remainder of President Cleveland's term.
- John Sherman - Resigned due to declining health. He was 73 when first appointed, and the President took council more from Assistant Secretary of State William Day than him.
- William R. Day - Resigned after 5 months to work on the U.S. Peace Commission formed to negotiate an end to the Spanish-American War. Later served as Associate Justice on the Supreme Court.
- John M. Hay - Died in Office from heart ailment and complications.
- Elihu Root - Resigned after being elected Senator from New York.
- Robert Bacon - Served the final 38 days of President Theodore Roosevelt's term after Root's resignation.
- Philander C. Knox - Served throughout President Taft's term.
- William J. Bryan - Resigned in protest to President Wilson's belligerant tone towards Germany after the sinking of the Lusitania.
- Robert Lansing - Resigned after President Wilson suffered a stroke and susequent illness. Lansing proposed Vice President Marshall assume the Presidency, and Wilson's wife Edith asked for his resignation.
- Bainbridge Colby - Served the remainder of President Wilson's term.
- Charles E. Hughes - Resigned. President Harding died and was succeeded by President Coolidge, Hughes resigned after Coolidge was re-elected. Was later Chief Justice of the Supreme Court.
- Frank B. Kellogg - Served throughout President Coolidge's term.
- Henry L. Stimson - Served throughout President Hoover's term.
- Cordell Hull - Resigned due to failing health after 11 years under President Roosevelt and during World War II.
- Edward R. Stettinius, Jr. - Resigned to take up position as first U.S. Ambassador to the United Nations.
- James F. Byrnes - Resigned after being named TIME Man of the Year caused interpersonal issues between him and President Truman.
- George C. Marshall - Resigned due to ill health.
- Dean G. Acheson - Served the remainder of President Truman's term.
- John F. Dulles - Resigned due to ill health.
- Christian A. Herter - Served the remainder of President Eisenhower's term.
- David Dean Rusk - Served throughout President Kennedy and President Johnson's terms.
- William P. Rogers - Resigned. Some believe it is because he was continuously sidelined in favor of National Security Advisor Henry Kissinger.
- Henry A. Kissinger - Served the remainder of President Nixon's and President Ford's terms.
- Cyrus R. Vance - Resigned in protest to President Carter agreement to attempt to rescue hostages in Iran without informing him.
- Edmund S. Muskie - Served the remainder of President Carter's term.
- Alexander Haig - Resigned after causing a few scandals of his own (such as suggesting a nuclear warning shot in Europe to counter Soviet aggression).
- George P. Shultz - Served the remainder of President Reagan's term.
- James A. Baker - Resigned to become President George H.W. Bush's Chief of Staff.
- Lawrence S. Eagleburger - Served the remainder of President George H.W. Bush's term.
- Warren M. Christopher - Resigned after President Clinton's first term.
- Madeleine K. Albright - Served the remainder of President Clinton's term.
- Colin L. Powell - Resigned after being asked to by Chief of Staff Andrew Card.
- Condoleezza Rice - Served the remainder of President Bush's term.
- Hillary R. Clinton - Resigned after indicating she did not wish to serve a second term under President Obama.
- John Kerry - Served the remainder of President Obama's term.
- Rex Tillerson - Replaced by CIA Director Mike Pompeo (subject to official announcement and Senate confirmation) after a rocky relationship with President Trump.