The 36-year-old was an unused substitute as Juve beat Bologna 4-1 away to snatch a Champions League spot from Napoli, who were held by Hellas Verona.
Despite missing a league game for just the fifth time in 2020-21, Ronaldo finished on 29 goals, five more than his nearest rival, Inter striker Romelu Lukaku.
Ronaldo has become the first player to finish as the top scorer for a season in Serie A, LaLiga and the Premier League.
The Portugal star won three Pichichi trophies while at Real Madrid – in 2010-11, 2013-14 and 2014-15 – and won the Premier League golden boot with Manchester United in 2007-08.
Only Lionel Messi (30) and Robert Lewandowski (41) have scored more top-flight goals this season than Ronaldo among Europe’s top-five leagues.
Ronaldo has scored 81 Serie A goals in 97 appearances since joining Juve from Madrid in 2018, at least 10 more than any other player in that time.