Inter are 13 points clear in first place with four games remaining, and their triumph ends a run of nine consecutive title wins for Juventus.
Large crowds of flag-waving fans gathered outside the iconic Duomo in Milan to celebrate a long-awaited success that has broken the domestic dominance of rivals Juve.
The league title is Inter's first since winning the Serie A, Coppa Italia and Champions League Treble in 2009-10 under Jose Mourinho, and their 19th overall.
Inter have therefore overtaken AC Milan, who have 18 Serie A titles, to become the second-most successful club in league history behind Juventus, with 36 league wins.
Defending champions Juve have struggled this season under rookie coach Andrea Pirlo and are involved in a fierce battle to qualify for next season's Champions League.
The Turin club are fifth with 66 points, 16 behind Inter at the top of the table, while Inter's nearest challengers Atalanta and AC Milan have 69 points.
Juve chairman Andrea Agnelli congratulated his Inter counterpart Steven Zhang on Twitter.
"Well done Steven! Happy for you and proud of being your loyal opponent on the pitch and friend off the pitch. We'll be back...," he wrote.
Conte's side have looked destined to claim the league crown for most of the season after showing a level of relentless consistency that their rivals could not match.
Inter have topped the league standings for the last 13 rounds since beating Lazio 3-1 on Feb. 14.
They are unbeaten since Jan. 6, a run of 18 games, and became the first Italian side to begin the second half of a Serie A season with 11 consecutive wins between Jan. 30 and April 11.
Inter also boast the best defensive record in the league with 29 goals conceded in 34 games.
It marked an improvement on a runners-up spot in Conte's debut season in 2019-20, when Inter finished one point behind Juventus and were beaten 3-2 by Sevilla in the Europa League final.
Conte celebrates the fourth Serie A title of his coaching career, after guiding Juventus to the first three crowns of their nine-year run between 2011 and 2014.
Inter defeated Crotone 2-0 on Saturday to move up to 82 points, and Atalanta's draw ensured it was mathematically impossible for any of the chasing pack to catch them.