Do I need to hire a compliance officer?

That is not a requirement. Depending on the standard you are implementing, you might be required to assign the role of security officer (ISO 27001) or quality manager (ISO 9001), but this does not have to be a dedicated person.

For example, the role of security officer can also be assigned to your CTO or a security-minded engineer. The role of quality manager can be assigned to the COO or a project manager.