The superstar of the sandalwood industry, Ambareesh, was a dedicated parliamentarian, Naidu tweeted.
"Sad to hear about the sudden demise of Ambareesh. He was not only a great actor but also a dedicated parliamentarian. My condolences to his family, friends and followers," Naidu said.
Modi condoled Ambareesh's death saying the actor will be remembered for his memorable performances and extensive contribution to politics.
The rebel actor, who died at a private hospital in Bengaluru late on Saturday, was described by Modi as "a strong voice for Karnataka's welfare, at the state and central level".
Congress President Rahul Gandhi said his party has lost a valuable member. "He was a famous son of Karnataka, whose work as an actor and in politics, won him a huge following both in the state and across India."
Ambareesh died at around 10.15 p.m. after a massive cardiac arrest a couple of hours after he was brought to the Vikram Hospital following breathing trouble.
A former cabinet minister in the previous Congress government in Karnataka from May 2013 to June 2016 before then Chief Minister Siddaramaiah sacked him along with 13 other ministers in a major reshuffle, the Kannada star enjoyed huge respect across party and linguistic divide.
Tamil superstar Rajinikanth, multi-lingual actors Prakash Raj, Raadika Sarathkumar, Kannada actors Shiva Rajkumar, Puneeth Rajkumar, popular Telugu actor Chiranjeevi and several others from the south Indian film industry paid their homage to the actor.
"Grieved to learn of the passing of a colleague Ambareesh. Condolences and prayers," Bollywood megastar Amitabh Bachchan tweeted.
Chief Minister H.D. Kumaraswamy, Janata Dal-Secular (JD-S) supremo and former Prime Minister H.D. Deve Gowda, Bharatiya Janata Party (BJP) state unit president B.S. Yeddyurappa and ministers from the JD-S-Congress cabinet also paid their respects.
The Karnataka government has declared a three-day mourning and a state funeral for the actor-politician starting Monday.
The actor is survived by his widow and multi-lingual actress Sumalatha and son Abhishek.
Ambareesh entered films as 'Jaleel' in veteran director Puttanna Kanagal's "Naagarahaavu" in 1972.