Kammala jumla mai zuwa: Rooney ya fara yin wasan kwaikwayo a cikin vaudeville a matsayin ɗan wasan kwaikwayo na yara, kuma ya fara fim dinsa a lokacin da yake da shekaru 6. Ya taka rawar gani a cikin shahararren "Mickey McGuire" jerin gajeren fina-finai 78, daga shekaru 7 zuwa 13. A 14 da 15, ya taka leda a Puck a wasan kwaikwayo da kuma fim din da ya biyo baya na "A Midsummer Night's Dream". A lokacin da yake da shekaru 16 ya fara wasa da Andy Hardy, kuma ya sami sanannun farko a 17 a matsayin Whitey Marsh a "Boys Town". A lokacin da yake da shekaru 19, Mickey Rooney ya zama na biyu mafi ƙanƙanta a cikin 'yan wasan kwaikwayo mafi kyau a cikin jagorancin jagorancin kuma matashi na farko da za a zabi shi don Academy Award don aikinsa a matsayin Mickey Moran a 1939 fim din da ya dace da Broadway mai suna "Babes in Arms"; an ba shi lambar yabo ta musamman ta Academy Juvenile a
A shekara ta 1939. Rooney ya sami lambar yabo ta biyu ta Academy a cikin wannan rukuni don rawar da ya taka a matsayin Homer Macauley a cikin "The Human Comedy". A 23, hakan ya sa ya zama na uku mafi ƙanƙanta a cikin wannan rukunin kafin Timothée Chalamet mai shekaru 22 ya zarce shi saboda rawar da ya taka a matsayin Elio Perlman a cikin fim ɗin wasan kwaikwayo na soyayya mai zuwa "Kira Ni da Sunanka", a cikin 2017, shekaru 74 daga baya.