At 35, Shah becomes one of the youngest leaders in Nepal’s recent history and the first from the Madhesi community to hold the office.
He took the oath in Kathmandu on Friday, in a ceremony attended by top officials and foreign diplomats.
Shah, who rose to prominence as a musician before entering politics, led his Rastriya Swatantra Party to a commanding majority—winning 182 out of 275 parliamentary seats.
The vote followed months of unrest, including anti-corruption protests last September that turned deadly, leaving dozens killed.
Now in office, he faces the challenge of stabilising a country long troubled by political instability and slow economic growth.
His administration is expected to prioritise job creation and respond to calls for accountability over the crackdown on protesters.
Analysts say his early decisions on governance reforms and justice will be closely watched.
Nepal has seen more than 30 governments since 1990, with none completing a full term.
The opposition Nepali Congress came a distant second, while the Communist Party of Nepal led by former Prime Minister K.P. Sharma Oli placed third.
Shah’s rise signals a shift in public mood, driven largely by younger voters demanding change.
