"On the behalf of the Indian National Congress, I extend my heartiest congratulations to Anura Kumara Dissanayake on being elected the Executive President of the Democratic Socialist Republic of Sri Lanka," Kharge said in a post on X.
"India and Sri Lanka have a rich legacy of multifaceted cooperation and interaction, which dates back centuries, the Congress President said, adding that India looks forward to "strengthening our ties and shared values for the benefit of our region."
Earlier on Sunday, Prime Minister Narendra Modi also extended his congratulations to Dissanayake for securing the win and being elected as the 9th Executive President of Sri Lanka.
India's High Commissioner to Sri Lanka, Santosh Jha, also called on Dissanayake and conveyed greetings from India's leadership.
Sri Lanka's Marxist-leaning leader Dissanayake of Janatha Vimukthi Peramuna (JVP) party will be sworn in as the country's ninth - also, the first Leftist - President on Monday, following his triumph in the island nation's first presidential election since its worst-ever economic crisis.
The result was decided Sunday evening after Sri Lanka's first-ever presidential run-off with the counting of second preference votes following both Dissanayake and Samagi Jana Sandhanaya candidate Sajith Premadasa failing to get the required percentage of votes.
According to Sri Lanka's Election Commission, Dissanayake won the presidency with 42.31 per cent of the vote, with Premadasa finishing second and incumbent President Ranil Wickremesinghe, who was eliminated after the first round, in third position.
The election, held on Saturday, saw Dissanayake lead over veteran political figures such as incumbent President Ranil Wickremesinghe and Opposition leader Premadasa.
Dissanayake now stands on the cusp of making history as the country's first leftist President, heralding what could be a significant political shift for the South Asian island nation.