Rammohan was declared elected as Mayor by District Magistrate and presiding officer Rahul Bojja at a meeting of the newly-elected GHMC corporators.
Rammohan, who won from Cherlapally ward, has been a leader of TRS youth wing and played an active role in the separate statehood agitation for Telangana.
Baba Fassiuddin, corporator from Borabanda, was elected deputy mayor.
The ruling TRS in Telangana scored a thumping victory in the GHMC polls winning 99 out of the 150 wards.
Rammohan, who completed LLM and practised in the High Court as a lawyer, would take charge tomorrow.