The Italian champion handed first starts of the season to four players and trailed 1-0 to a fine Miguel Veloso strike before Ramsey got off the mark for his new club.
Ronaldo scored the winner from the penalty spot early in the second half as Juve, which was held by Fiorentina last weekend and squandered a two-goal lead to draw 2-2 with Atletico Madrid in midweek UEFA Champions League action, returned to winning ways in Turin against an opponent that finished with 10 men because of Marash Kumbulla's stoppage-time dismissal.
The victory lifts Juventus to the top of Serie A, albeit with the champion having played a game more than the chasing pack, and it was a particularly special one for Gianluigi Buffon, who equalled Paolo Maldini's record of 902 club appearances with a rare start.
Yet it could have turned out differently for Buffon as Verona were gifted a penalty 19 minutes in when Merih Demiral fouled Samuel Di Carmine inside the box.
Di Carmine slammed the penalty against the foot of the post and Darko Lazovic picked out the crossbar from the follow-up, but the ball was in the net 13 seconds later through Veloso's unstoppable drive into the top-left corner.
Juventus had scored in its previous 12 home league meetings with Verona, however, and it was soon on level terms through Ramsey's deflected shot from 25 yards.
The hosts moved in front inside four minutes of the second period as Koray Gunter needlessly challenged Juan Cuadrado and Ronaldo thumped the resulting penalty down the middle.
Buffon produced a brilliant stop to deny Lazovic in the final minute, but Verona's hopes of snatching a point were effectively ended when Kumbulla tripped Blaise Matuidi and was shown a second yellow in stoppage-time.
Juventus has won three and drawn two of its opening five matches under Maurizio Sarri but has been far from convincing in those matches.
The ex-Chelsea boss had every right to rotate his squad for this contest, but it appears he is still working out the best players to suit his system.
Juventus travels to Brescia on Wednesday (AEST) for the first midweek Serie A action of the season and Verona hosts Udinese the same day.