Six Secretaries of State have become Presidents as of 2015; including five of the first ten Secretaries - Jefferson, Madison, Monroe, Quincy Adams, and Van Buren. A former Secretary has not been elected President in 156 years since James Buchanan's appointment under Polk in 1845.

1. Thomas Jefferson: SoS (1789-94), PotUS (1801-09)

2. James Madison: SoS (1801–09), PotUS (1809–17)

3. James Monroe: (1811-14), PotUS (1817-25)

4. John Quincy Adams: SoS (1817–25), PotUS (1825–29)

5. Martin Van Buren: SoS (1829-31), PotUS (1837–1841)

6. James Buchanan: SoS (1845-49), PotUS (1857–61)

More Info: www.quora.com