The ATO is a non-corporate Commonwealth entity within the Treasury portfolio and serves two Ministers:
Treasurer, the Hon Scott Morrison MP
Minister for Revenue and Financial Services, the Hon Kelly O'Dwyer MP.
The ATO is led by Chris Jordan AO, Commissioner of Taxation and Registrar of the Australian Business Register, and is supported by the Executive Committee and various other corporate committees.
Source: this is an extract from the company's own website.