Is it necessary to justify the gap in studies by joining a company before applying for the next intake?

No, you do not need to join a company to justify a gap in your studies before applying for your next intake.

What matters is how you explain the gap in your application, especially in your Statement of Purpose (SOP). You should clearly show how you used that time productively - such as through skill development, certifications, volunteering, or personal growth. If you can demonstrate the gap was meaningful and relevant to your goals, Irish universities will consider your application even without recent employment.