Ka kammala wannan magana: Ya ciyar da lokacinsa na kyauta yana sassaka da kuma nunawa kuma kwarewarsa ta halitta ta sa ya fara aiki a matsayin mai tsarawa a ofishin gine-gine sannan kuma a matsayin mai zane-zane na wasanni don "San Francisco Daily News". A wannan lokacin ya kuma zama dan wasan dambe na kwararru, ya ci wasanninsa na farko tara amma ya yi ritaya bayan rashin nasara na goma. Daga baya ya yi aiki a layin dogo, da farko a matsayin mai hana birki kuma daga baya a matsayin mai binciken ƙasa, a matsayin ƙwararren mai zanen marmara, kuma ya kasance mataimakin babban masanin gine-ginen gidan.
1915 San Francisco World's Fair, inda aka nuna wasu ayyukansa. A wannan lokacin ya yi samfuran, gami da dinosaur da kuma kogon dutse, wanda ya motsa tare da taimakon mai ɗaukar hoto na gida. San Francisco mai nunawa Herman Wobber ya ga wannan gwajin na 90 na biyu kuma ya umurci O'Brien ya yi fim dinsa na farko, "" (1915) don kasafin kuɗi na $ 5,000.