On a humid morning in Tanzania on Tuesday, two American presidents stood side by side in a ceremony where neither spoke. One was the son of a Kenyan whose election broke barriers for African-Americans. But it was the other one who might command as much, if not more, respect among many Africans today.

While George W. Bush is remembered at home for war, terrorism and national security, in Africa he is seen as a lifesaver who as president helped arrest a deadly epidemic and promoted development of impoverished lands. Now out of office, he has devoted his post-presidency in part to continuing to aid the world’s poorest continent.

The coincidence of Mr. Bush’s trip to Africa overlapping with President Obama’s own journey this week threw a rare public spotlight on the mission the 43rd president has chosen for himself since leaving office more than four years ago. Building on the health care programs of his presidency, he has quietly returned to Africa three times, renovating health clinics and expanding screening and treatment programs to fight cervical cancer.

For a leader whose administration was consumed by conflict and death, Mr. Bush’s former advisers say the Africa ventures offer a way to focus on life. As his travels center on lifting up the destitute, they evoke the presidency that might have been had there been no Sept. 11 attacks and no war in Iraq, a presidency that might have been free to focus more on the “compassionate conservative” agenda he embraced on his way to the White House.