Complex sentence: He started MyWritingProfessor.com where he serves as the Owner and Principal Consultant and as a longstanding advocate for youth, he accepted a position at the Center on Halsted where he has just been promoted to serve as their Director of Youth Services.
Split into simpler sentences: He started MyWritingProfessor.com where he serves as the owner and principal consultant, and remains a longstanding advocate for youth. He accepted a position at the Center on Halsted where he has just been promoted to serve as the director of youth services.