The voice actors were chosen for how they fit and could add to the characters – for instance, James Earl Jones was cast because the directors found his voice "powerful" and similar to a lion's roar.[16] Jones commented that during the years of production, Mufasa "became more and more of a dopey dad instead of [a] grand king".[17]

Nathan Lane originally auditioned for Zazu, and Ernie Sabella, for one of the hyenas. Upon meeting each other at the recording studio, the actors, who at the time both co-starred in Guys and Dolls, were asked to record together as hyenas. The directors laughed at their performance and decided to cast them as Timon and Pumbaa.[16][18] For the hyenas, the original intention was to reunite Cheech & Chong, but while Cheech Marin accepted to play Banzai, Tommy Chong was unavailable. Thus his role was changed into a female hyena, Shenzi, who was voiced by Whoopi Goldberg.[10]

Matthew Broderick was cast as adult Simba early during production, and during the three years of voice acting only recorded with another actor once, and only discovered Moira Kelly voiced Nala at the premiere.[19] Jeremy Irons had at first refused the role due to not being comfortable going from the dramatic performance as Claus von Bülow in Reversal of Fortune to a comedic role. But once he came in, Irons' performance even inspired the writers to incorporate more of his acting as von Bülow — even adding one of that character's lines, "You have no idea" - and animator Andreas Deja to watch both Reversal of Fortune and Damage to pick up Irons' facial traits and tics.[1