ɪn nˈaɪntiːnhˈʌndɹɪd twˈɛnti θɹˈiː, æɾ ˈeɪdʒ twˈɛnti fˈaɪv, sˈɑːnənbˌɜːɡ tˈɜːnd pɹəfˈɛʃənəl, plˈeɪɪŋ ɪnðɪ ˌɛnˌɛfˈɛl fɚðə bˈʌfəlˌoʊ ˈɔːl ɐmˈɛɹɪkənz wˈʌn ɡˈeɪm ænd ðə kəlˈʌmbəs tˈaɪɡɚz.
In 1923, at age 25, Sonnenberg turned professional, playing in the NFL for the Buffalo All Americans (one game) and the Columbus Tigers.