But the unveiling faced scorn on social media after she started to sing while addressing the crowd.
"I know two girls that I just adore," crooned Mrs Fiorina, in reference to Cruz's two daughters, Caroline and Catherine. "I'm so happy I can see them more. 'Cuz we travel on the bus all day; we get to play."
Twitter users reacted with bewilderment, mocking Fiorina over her singing.
@youngsinick: Carly Fiorina started singing at a rally where she's named by VP by a candidate who ain't getting the nod. This election is hilarious.
"Carly Fiorina started singing at a rally where she's named VP by a candidate who ain't getting the nod," tweeted writer and Ebony columnist Michael Arceneaux. "This election is hilarious."
"Whoever vetted the singing portion of Carly's (hypothetical) VP nom acceptance speech should probably be fired like right now," tweeted TPM editor Allegra Kirkland.
Cruz praised Fiorina as a principled fighter for conservative values who knew how to create jobs and would be a valuable ally on the campaign trail.
- Reuters, Telegraph Group Ltd