The Real striker and his former manager also shared a brief exchange just inside the players’ tunnel shortly after full-time.
Ronaldo helped lead Real Madrid to an emphatic 4-1 win over Juventus at the Principality Stadium on Saturday night.
The Portuguese scored goals either side of the half as Zinedine Zidane’s men became the first group of players to win back-to-back Champions League titles.
Casmiro and Marco Asensio scored the other two Real goals of the game.
The 32-year-old spent six seasons under Ferguson at Manchester United and built up a special connection with the former Red Devils boss.
During his time at Old Trafford, Ronaldo won three Premier League titles, one FA Cup, two League Cups and one Champions League.
Ferguson waited for Ronaldo just inside the players’ tunnel where the pair shared a hug.
Ronaldo still referred to his former mentor as his boss, saying “Hello boss how are you?” when he saw Ferguson.
The Old Trafford legend then presented the Real striker with the man of the match award.