In addition to the disagreement on the Iran deal, Tillerson did not see eye to eye with Trump's policies toward China, while Pompeo did, particularly with his Tea Party background, according to an insider who worked with the former Kansas congressman while serving as an adviser to the Trump transition team.
During his time in the job, he was faced with an extraordinary array of foreign policy challenges - from North Korean nuclear threats, to Russian intervention in Ukraine, Syria and Western elections, to attacks on United States diplomats in Cuba.
Mr Tillerson's sacking comes shortly after Mr Trump, without consulting his top diplomat, chose to accept an invitation to talks with North Korea's Kim Jong-Un on resolving the Korean nuclear stand-off.
"Tillerson and the president have not meshed well, but at the same time I thought he did a lot for the president by providing an image of stability", Cyr said. A researcher at the University of Chicago, who plotted the time of day that Trump tweets, found an extremely dense band between 6 a.m. and 9 a.m., precisely when Fox and Friends is on the air.
Whatever reputation for understatedness diplomats possess went out the door throughout Tillerson's calamitous State Department tenure.
"I think the world of Gina", Clapper said.
Tillerson in 2017 paid a courtesy call to President Rodrigo Duterte in the wake of his string of stinging retorts against Washington's criticism of his war on drugs.
Sen. Dianne Feinstein (D., Calif.) on Tuesday said that Gina Haspel has been a "good deputy director of the Central Intelligence Agency", but said that she would wait until the confirmation hearing to determine whether she will vote for Haspel to be the next director of the Central Intelligence Agency. Tillerson, the White House said, asked that Trump wait until he returned to the US, and he shortened his trip to Africa - where much of his mission revolved around softening the impact of Trump's recent reported criticisms.
Although relatively new to the Trump inner circle, Pompeo has won the president's trust with tailored briefings on classified information.
The Tillerson sacking comes at a sensitive moment in global relations as the president prepares to meet the leader of North Korea for the first time.
Goldstein was sacked by the White House shortly after issuing the statement. Gary Cohn recently announced his resignation as director of the National Economic Council.
In his farewell speech, Tillerson also notably failed to thank Trump, but he did mention Russian interference in the 2016 election.
U.S. Sen. Ron Johnson, R-Wis., issued a statement: "Secretary Tillerson served admirably in a very hard job and I have a great deal of respect for him". A number of details still need working out ahead of the summit, from the time and place to the actual agenda.
Iran is the single issue where the change from Mr. Tillerson - who helped to restrain Mr. Trump's urge to kill the nuclear agreement - to Mr. Pompeo is most likely to have a serious and destructive impact on policy.
Sen. Tom Cotton, R-Ark., who is consulting with the White House and Sen.
"And we commenced the steps to dramatically increase not just the scope, but the effectiveness of the sanctions" he said.
In choosing Pompeo, Trump has opted for one of his close allies.
This "fix" would expand the agreement to include restrictions on Iran's ballistic missile program and end the "sunset clauses" that allow Tehran to resume some enrichment within 10 years. "I look forward to meeting with Director Pompeo to discuss his nomination and learn more about his plans for running the State Department". Trump interviewed several other prospects at Trump Tower in NY, including former Gov. Mitt Romney, R-Massachusetts, before settling on the surprise choice of the former oil executive from Texas.