Walker spent over 23 years in the U.S. Navy, (17 years active and 6 in the Naval Reserve) reaching the rank of Commander.
wˈɔːkɚ spˈɛnt ˌoʊvɚ twˈɛnti θɹˈiː jˈɪɹz ɪnðə jˈuː.ˈɛs. nˈeɪvi, sˈɛvəntˌiːn jˈɪɹz ˈæktɪv ænd sˈɪks ɪnðə nˈeɪvəl ɹɪzˈɜːv ɹˈiːtʃɪŋ ðə ɹˈæŋk ʌv kəmˈændɚ.