The midfielder, who has been a San Paolo resident for six years, and the club president have confirmed the Slovakia star has signed a contract until 2018
The Slovakia international, who has been with the Naples club since 2007, has become one of the hottest properties in European football at the Stadio San Paolo.
The 26-year-old confirmed his renewal after the Partenopei's 2-1 friendly win over Benfica on Friday, revealed his hope that compatriot Martin Skrtel joins from Liverpool and predicted a top debut season from Gonzalo Higuain.
"I have just renewed my contract with Napoli until 2018 and I'm very happy," Hamsik told Mediaset Premium.
"I do not decide who we sign in the transfer market, but Skrtel's definitely a great player and would suit Napoli. Higuain? I think it will be a great year for him."
Napoli club president Aurelio De Laurentiis also spoke out with delight about Hamsik's renewal and praised the player for ignoring the attention of other top teams to be a key figure for Rafael Benitez's men.
"It’s a perfect marriage with Hamsik," he wrote on Twitter. "He is a great man, a great professional and a great player who honours the Napoli jersey.
"It is a shirt he is happy and satisfied to honour. We have renewed his contract, extending it to 2018."
Higuain, who scored his first goal for the Naples-based club since his move from Real Madrid earlier this summer to secure the win over Benfica, revealed the home crowd had given him goosebumps following the triumph.
"I am very happy to have scored my first goal at the San Paolo," the Argentine said. "I really hoped to score tonight and to give my first goal to the fans. I managed it and I am really happy.
"Hearing the noise of the crowd at my goal and them chanting my name was an amazing experience, it gave me goosebumps. I thank the Neapolitans for this splendid evening and for all the warmth they are giving me."