Frozen and Frozen are two of the greatest films of all time. Well, my opinion might be slightly biased, because as you know, I kind of like Elsa. When I say kind of, I think that she's the coolest thing ever.
Anyways, an important attribute of animated films is having a good cast of voices. Voice acting requires being able to give a convincing performance without the benefit of being physically expressive. Thankfully, both Frozen films have quite the impressive cast.
Frozen introduced me to Idina Menzel. If you ask me, she's one of the greatest singers of all time. In fact, she's one of my top two singers to ever perform in any Disney production, right up there with Tony Jay from The Hunchback of Notre Dame. Frozen also helped me gain a large appreciation for Alan Tudyk. Since appearing in Frozen, Alan Tudyk has continued giving great vocal performances in both shows and films.
From both films:
Kristen Bell as Princess Anna
Idina Menzel as Queen Elsa
Jonathan Groff as Kristoff
Josh Gad as Olaf
Alan Tudyk as the Duke of Weselton in the first film. In the second film, he voiced a Northuldra leader, a soldier and a guard.
Ciarán Hinds as Grand Pabbie
Maia Wilson as Bulda
Stephen J. Anderson as Kai
Paul Briggs as Marshmallow
From the first film:
Santino Fontana as Prince Hans
Maurice LaMarche as King Agnarr
Jennifer Lee (who co-directed the film) as Queen Iduna
Edie McClurg as Gerda
Chris Williams as Oaken
From the second film:
Sterling K. Brown as Lieutenant Mattias
Alfred Molina as King Agnarr
Evan Rachel Wood as Queen Iduna
Martha Plimpton as Yelena
Rachel Matthews as Honeymaren
Jason Ritter as Ryder
Jeremy Sisto as King Runeard
Aurora as the Voice
Kristen Bell and Idina Menzel also voiced the Frozen sisters in the second Wreck-It Ralph film. Both of them, along with Jonathan Groff and Josh Gad, also did voicework in some Frozen shorts.
In the second film, Hans and the Duke's dialogue is audio taken from the first film.
Oaken appeared in the second film, but he didn't have any dialogue.
King Agnarr and Queen Iduna were recast in the second film. That might be because they have more dialogue and more prominent roles in the second film.