I think it's better to say: 'Hasta que empezó a trabajar como actor, realizó muchos trabajos'. 'Pasado simple' or 'pretérito perfecto' instead of 'pretérito imperfecto'. I think it's 'hizo' (pretérito perfecto) because it's a finished action, that stopped when he started working as an actor. I hope you get better answers. Good luck!

I would user Tener and say ... tenía muchos trabajos. Although I'm only a Spanish student not a native speaker.