Jacksepticeye

Seán William McLoughlin, better known by his online pseudonym Jacksepticeye or simply Jack, is an Irish YouTuber and one of Markiplier and PewDiePie's best friends. He and Mark have some collaboration videos together. He has played in Co-op Quartet with Mark, Wade and Bob, and also appeared in a few Unus Annus videos.

Early life
Seán William McLoughlin was born on 7 February 1990, in County Offaly, Ireland. His mother is Florrie McLoughlin (born 1969) and is Roman Catholic. He is the youngest of five siblings, having two older sisters, Allison and Susan, and two older brothers, Malcolm and Simon.

He was the former drummer of an indie heavy-metal band named Raised to the Ground. In the late 2000's, he graduated high school.

In the early 2010's, McLoughlin dropped out of college after two years whilst studying Music Technology in Limerick, Ireland. He finished college the second time around fall 2014, the same year that his channel reached 1 million subscribers.

Career
Jack created his YouTube channel on February 24th 2007, although he didn't start making his own videos until November 2012, his very first upload being a Metal Gear Solid 4 impression on Solid Snake. According to Jack in a 2017 video, he originally wanted the channel to be dedicated to impressions.

Whilst playing Battlefield 3, Jack searched for tips online and came across LevelCapGaming. Jack was also a fanboy of Markiplier and PewDiePie, becoming part of his inspiration to start his own channel. Lacking friendships and living in a remote area, he turned to YouTube so he could create an online community, despite being pressed for time to make videos since he was also studying for exams in college. In September 2013, he entered PewDiePie's shout out competition and was one of several channels who won, where he went from 2,000 to 15,000 subscribers and pounced upon the opportunity to improve. Mark noticed Jack by writing on Twitter that he had entertaining videos, resulting in their first ever collaboration being "Gmod Sandbox w/ Markiplier | DON'T WORRY....WE'RE SCIENTISTS."

From 2012 until 2014 Jack lived beside his parents in a cabin, causing issues with his internet affecting his uploads. He had to use a camera as his microphone and attempted to hide his Irish accent by pretending to be American for fear of being made fun of.

In 2014, he moved to an apartment in Athlone for better internet access. He graduated from college that same year and earned a degree in hotel management. In 2016, Jack hired Robin as his first editor. For the first time in five years in October 2017, there were no scheduled uploads for a week due to Jack touring with the Game Grumps.

Jack kick started 2018 with the motto, Positive Mental Attitude ('PMA' for short), which turned into a merchandise line released in August 2018. Between July and October 2018 he took an extended break to Los Angeles. His previous upload schedule was two videos per day seven days a week, although has since decreased beginning on July 20th, 2018; during August 2019 he resumed his former schedule.

While his main focus is on game plays of a variety of different genres, from indie to horror to upcoming releases, he occasionally does vlogs and sketch comedy. He is known for his energetic and caring personality, but tones down to seriousness when something needs to be talked about. He has shown his appreciation for his fanbase multiple times, such as making a subscriber milestone video thanking them.

Meeting Markiplier
Jack and Mark first met on Twitter, where Mark had found his channel and private messaged him to start a conversation. Despite the fact that Mark was the first one to make a move, Jack had actually been a huge fan of Mark long before and basically started his whole channel because of him. He says that he admires the way that Mark made YouTube about the fans and not the numbers, and he follows that code just as much as he would. Even now, after an entire year of knowing him, Jack still says that he looks up to Mark dearly and respects and cares about him greatly. Their very first collaboration video was published on April 25th, 2014.

Gmod
Jack and Mark have played Garry's Mod Sandbox together, one time with PewDiePie. The "Gmod Sandbox w/ JackSepticEye" video was their first collab video ever. At first, Jack tried seriously to do something, but after constant Mark's interference's, he accepted to participate in rocket launches. At Prop Hunt with Jack usually plays on the same team as Mark and follows his instructions.

The Forest
While Jack and Mark were playing The Forest. Jack has confirmed that he is immune to Mark's provoking and stated that it is impossible to offend the Irish. Their ship name, Septiplier, was joked about.

GTA V
Jack is one of the players in Mark's Grand Theft Auto V gameplay series. He managed to get a jet at one point and even accidentally shot down Mark in his helicopter. He crashed his jet during the most recent episode. Wade also killed Jack in the series and made Jack's body fly in the air with an SUV.

Other
Mark has photoshopped Jack to make him a leprechaun on a Happy Wheels Billy. In one of Jack's videos, Mark along with Jack and two other people played Cards Against Humanity. He's also a guest on the Five Nights at Freddy's Gmod maps as well. Jack has also appeared on a few episodes of Unus Annus first appearing in Donating Toys to Charity w/ JackSepticEye and also appearing in 2 Men 200 Accents and Preserving Ourselves In Wax.

Quotes
"Top of the mornin' to ya, laddies! My name is Jacksepticeye, and welcome (back) to [game name]!"

- Seàn's classic intro

Trivia

 * Jack's signature "top of the mornin' to ya laddies" phrase was inspired by Monica Geller's Irish impression from Friends. The slap came later on and he incorporated it into his intro.
 * Jack is the most subscribed YouTuber channel in the Republic of Ireland.
 * Jack is 5 feet 10 inches, same as Mark.
 * Jack's imitation of Mark is done in the voice of Wilford Warfstache.
 * Whenever Mark tries to impersonate Jack, Mark uses a Scottish accent instead of an Irish accent.
 * Jack was originally supposed to appear in an episode of Drunk Minecraft but was canceled following an incident with Mark being told not to drink ever again leading to the series' cancellation.
 * Markiplier mistakenly capitalizes the second and third word in Jack's alias, writing "JackSepticEye" instead of its correct form "Jacksepticeye."