He spends his days annoying his co-workers at Wernham Hogg with his rigid enforcement of the rules and sycophantic attitude towards David Brent, whom he views as a friend.

"[2] Gareth flaunts his "team leader" status, despite his desk mate, Tim Canterbury, highlighting that it is a meaningless title simply entailing more responsibility for the same pay.

Tim plays numerous pranks on Gareth, such as hiding his computer, putting his stapler in jelly (a prank that has been reprised in several other versions of The Office, including the US version), gluing his phone so that the receiver cannot be picked up (and then calling him) and playing on Gareth's naïveté by discussing warfare with language which could be interpreted as being homosexual in nature (e.g. "the enemy has discovered your camp...and they've all entered your hole", "taking a man from behind" or "could you give a man a lethal blow?").

Frequently comparing the mundane events that take place at Wernham Hogg with equivalent situations likely to occur on the battlefield, Gareth stresses the need for a shrewd, austere style of leadership.

When impugning Brent's injection of comedy into the workplace, he ridiculously attempts to justify his argument by suggesting that "in a battle situation" soldiers would be more likely to be inspired by a "decisive, uncompromising leader" than one who offered them jokes before their advance towards the enemy.

Following Brent's departure, Gareth is made regional manager of the branch, although he still seems to command little respect – Tim's latest prank is to lock his boss in his office, requiring a desperate phone call to the receptionist's desk to secure his release.

He does, however, have several close friends, some of whom include "Jimmy the Perv" (who lives up to his name by repeatedly paying Dawn Tinsley for kisses for Comic Relief, with increasing lasciviousness each time), "The Oggmonster" (a very tall figure with astigmatism, played by The Office co-creator Stephen Merchant) and unseen characters known only by the nicknames "Fish Fingers" and "Gobbler".