How do you become America’s Number 1 diplomat?

First, a president must decide you’re the best person for the job, as President Trump did in tapping Rex Tillerson, retired chairman and CEO of Exxon Mobil, and then the Senate must give its consent, as it did February 1.

Tillerson is the 69th secretary of state in an illustrious line stretching back to Thomas Jefferson. (Two served twice under different presidents.)

Several, like Tillerson, came from the business world, including George Shultz, who was president of the Bechtel construction firm.

Tillerson, 64, is the first secretary of state with an engineering degree, although John Sherman briefly worked as a civil engineer before becoming a lawyer and senator.

Full biographies on the State Department’s Office of the Historian website tell the stories of the many roles played by secretaries of state, before and after their terms.

The most common profession for past secretaries of state? Fifty-two were lawyers.

Nearly half the secretaries served in the Senate or House, and 14 were governors.

Jefferson was the first of a half dozen who went on to become president, all before the Civil War. Three served as vice president and 19 ran for president.

Five were generals, including George Marshall, whose plan to rebuild Europe after World War II earned him a Nobel Peace Prize. Four other secretaries of state also were Nobel laureates for peacemaking efforts: Elihu Root, Frank Kellogg, Cordell Hull and Henry Kissinger.

Three women were secretaries of state, all since the 1990s: Madeleine Albright, Condoleezza Rice and Hillary Clinton.

The average tenure is 3.3 years. Elihu Washburne spent just 11 days in the job in 1869, while Hull served almost 12 years under President Franklin D. Roosevelt.

In the jet age, America’s top diplomat has needed to keep a bag packed. John Kerry broke Rice’s record by visiting 91 countries and logging nearly 2.3 million kilometers. Clinton, Kerry’s predecessor, traveled to 112 countries and traversed 1.5 million kilometers.