Can someone who majored in computer science become a mobile app developer? What other qualifications would be required for app development?

I know many great developers who never study computers. But if you really want it and ready to learn new languages and technologies every 6 months ))) then welcome to the club )))

it is easier for him to learn it and do it later , rather than new person who dose not has same level of knowledge.

but directly he can not it .