Scott McTominay scored with an acrobatic bicycle kick before half-time and Romelu Lukaku doubled the lead with a solo goal after the break in the decisive 2-0 home win over Cagliari on Friday.
McTominay was later named Italian Serie A's player of the season.
The Scotland midfielder has been vital for Napoli, scoring 12 goals and providing six assists in 34 league matches.
The 28-year-old former Manchester United player emerged as a key member of the Napoli team after Khvicha Kvaratskhelia moved to Paris St Germain in January.
"The sacrifice of every single player in this group is just incredible. The people deserve it, as they've been behind us from day one. For me to come here and experience this, it's just a dream," McTominay told DAZN.
In Naples he now goes by the name "McFratm" among supporters, a playful fusion of his name and "Fratm", the Neapolitan word for "my brother".
"My Italian is OK, I can understand, but speaking it takes more confidence and it's not easy. It is much easier to do it with people who don't speak any English. I can feel a lot of love," McTominay said, adding he just had learned the words "festeggiamo, andiamo", meaning "let's go celebrate".
Conte became the first coach to win the Italian championship with three different teams.
Napoli needed only to do the same or better than defending champion Inter Milan in the final round of matches, so Inter's 2-0 win at 10-man Como wasn't enough for the Nerazzurri.
The results meant Napoli finished Serie A one point ahead of Inter.
The southern squad's fourth Serie A title overall capped an impressive turnaround after the Partenopei finished 10th during a dismal title defence last season.
Maradona led Napoli to their first two titles in 1987 and 1990. The 2023 team led by Victor Osimhen and Khvicha Kvaratskhelia clinched with five rounds to spare.
Inter were heading toward the title until McTominay went airborne to redirect a cross from Matteo Politano in the 42nd minute.
Lukaku, who was signed from Chelsea in August, controlled a long vertical pass and dribbled past two defenders before scoring in the 51st. It was his 14th goal to go with his league-leading 10 assists.
Meanwhile for Inter, defender Stefan de Vrij scored 20 minutes in by redirecting a corner kick with a bouncing header.
Como were reduced to 10 men when goalkeeper Pepe Reina was sent off at the end of the first half for a foul on Mehdi Taremi. It was Reina's final game before retiring.
JoaquÃn Correa added another for Inter after the break in almost the same exact moment that Lukaku scored for Napoli.
Inter, who are also preparing for the Champions League final against Paris Saint-Germain in eight days, rested most of their usual starting lineup, including top strikers Lautaro Martinez and Marcus Thuram.
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