He previously served as the Minister of Medical - Health and Finance Department of Telangana from 8 September 2019 to 2 December 2023.

Harish Rao started his political journey with Bharat Rashtra Samithi as youth leader.

Soon, he became key member of Bharat Rashtra Samithi and started working as Internal party strategist.

In July 2010, the High Court of Andhra Pradesh ordered the Election Commission of India to conduct by-polls in Siddipet and other towns across the Telangana region.

Harish Rao contested again from Siddipet defeating opponent Babu Mohan (from the Telugu Desam Party) yet again.

Under Irrigation ministry, TRS government redesigned the project Pranahitha-chevella project on the grounds that the original plan had too many environmental obstacles and had very low water storage provision — only about 16.5 tmc ft. After conducting a highly advanced Light Detection and Ranging (LiDAR) survey for a couple of months, the government separated the original component serving the Adilabad area as the Pranahitha project and renamed the rest as Kaleshwaram by redesigning the head works, storage capacity and the canal system based on the data of availability of water at different locations along the course of the Godavari and its tributaries.

The project is designed to irrigate 7,38,851 hectares (over 18.47 lakh acres) uplands in the erstwhile districts of Karimnagar, Nizamabad, Warangal, Medak, Nalgonda and Ranga Reddy.

The Comptroller and Auditor General (CAG) of India has come out with a damning report on the project in Feb 2024, which says it was economically unviable from the start and details the massive cost overruns, possible undue benefits accrued to contractors for the supply and commissioning of pumps, motors, etc., and the poor planning involved.

The National Dam Safety Authority (NDSA) found that the Medigadda barrage is severely compromised, rendering it useless unless fully renovated.