ɹˈænəlz mˈuːvd tə nˈuː jˈɔːɹk sˈɪɾi ɪn nˈaɪntiːnhˈʌndɹɪd nˈaɪnti sˈɛvən ˈæftɚ hˈaɪ skˈuːl, stˈʌdiɪŋ θˈiəɾɚɹ æt mˈɛɹɪmˌaʊnt mænhˈæʔn̩ kˈɑːlɪdʒ fɔːɹ tˈuː jˈɪɹz bᵻfˌoːɹ hiː stˈɑːɹɾᵻd ɔːdˈɪʃənɪŋ fˈʊltˈaɪm ænd bɪɡˈæn lˈændɪŋ ɹˈoʊlz.
Rannells moved to New York City in 1997 after high school, studying theater at Marymount Manhattan College for two years before he started auditioning full-time and began landing roles.