He served as the Diwan of Baroda from 1927 to 1944, Prime Minister of Jaipur State from 1946 to 1949 and as a member of the Rajya Sabha from 1961 to 1964.

Krishnamachari served the Additional Secretary of the Madras Board of Revenue from 1913 to 1919 and was the trustee to the Vizianagaram estate from 1919 to 1922.

While serving as Diwan of Baroda, Krishnamachari launched a massive rural reconstruction programme in the princely state.

[2] In July 1947, following the decision to partition India, the Constituent Assembly modified its rules to have two vice-presidents, and there was a suggestion that one of them might be from the princely states.

When the assembly did elect these vice-presidents on 16 July, there were only two nominations, so Krishnamachari (Jaipur) was selected unopposed, along with Dr. Harendra Coomar Mookerjee (West Bengal).