Seán would later use the nickname as his username. When he was still in school, he sustained a severe injury when he was hit in the face with a football while wearing glasses which caused his eye to later become infected, and a bully began calling him 'Jack Septic Eye', after figuring out that Seán's mother called him Jack. The term “SepticEye” also came from his childhood. His mother and siblings gave him the nickname because the name Seán is the Irish variant of the name John, and a common nickname for people called John in Ireland and United Kingdom is Jack. The nickname “Jack” comes from his childhood. Seán returned to his YouTube channel on Augwith a livestream announcing his return to uploading content following his break. In a video released on July 2, 2020, Seán went on a month-long break due to mental health and the situations going on currently with YouTube and Twitch while explaining why he doesn't want to upload daily content because he needs to, he is taking a month off because he doesn't want to make YouTube videos at this time.

His channel is the 130th most subscribed channel on YouTube, and also the most subscribed channel in Ireland.

He is known for his energy, distinct accent, loud commentary and sometimes gentle nature and (currently old) signature green hair (which he dyed for charity alongside Markiplier). Seán 'Jack' William McLoughlin (born: Febru( ) ), better known online as jacksepticeye (or simply Jack), is an Irish YouTuber, video game commentator, occasional vlogger, voice actor, and founder of the clothes company CLOAK along with Markiplier. Hello all you beautiful people out there, my name is Jacksepticeye, and. (WAPOOSH) Top of the mornin' to ya, laddies! My name is Jacksepticeye, and welcome (back) to !

Clustertruck jacksepticeye