Final answer:
Herbert Hoover was the president who donated all of his presidential and congressional salaries to charity, exemplifying his belief in voluntary support over government assistance.
Step-by-step explanation:
The president who donated all of his presidential salary, as well as his congressional salary before that, to charity was Herbert Hoover. Herbert Hoover was known for his significant charitable contributions during his time in office. Despite his opposition to direct-relief federal government programs during his tenure, his actions showcased a deep personal sympathy for those in need.
Through the Great Depression, Hoover donated an average of $25,000 annually to various relief organizations.
His philosophy was rooted in individualism, believing this was the path toward long-term American recovery, and consistently emphasized the value of voluntary deeds over compulsory government actions as part of this belief.