May 1 was a public holiday, but South African Revenue Service Commissioner Edward Kieswetter was already ticking off tasks on his to do list, according to the tax agency.
This included declaring his interests and cutting ties where necessary, the revenue service said.
In a statement issued on Wednesday afternoon, SARS welcomed the commissioner to his new position.
"Today, Edward Kieswetter starts his role as Commissioner of the South African Revenue Service," the statement said.
"We welcome Kieswetter and look forward to working with him in rebuilding SARS."
Spokesperson Sandile Memela told Fin24 Kieswetter was a "man of principle".
The new Commissioner has already fully disclosed his outside interests and involvement in various organisations, Memela said.
He has submitted his resignation as Lead Independent Director of Shoprite and has previously resigned from the boards of African Unity and GEMS Education, Africa.
Other than personal private investments, his significant involvement includes directorships on Transnet and Technology Innovation Agency, both State-owned Enterprises, the statement said.
"Mr Kieswetter has expressed his full commitment to manage his personal affairs in a manner that creates public confidence."