The squad is a group of friends, most of whom have day jobs off the pitch which have nothing to do with sport.
And yet they have toured the US, Serbia, Ireland and Jersey, had their own kit custom-made by sportswear company Umbro and average 700,000 views per match.
They've also played at the UK's top stadiums including Wembley and the Etihad, as well as the O2 Arena and Everton's training ground.
And it's all thanks to a carefully crafted presence on YouTube.
The team did not start life as total unknowns, Captain Spencer Owen was already a successful football and gaming YouTuber in his own right, and now has nearly two million followers.
Sunday league activity already has an established YouTube presence - like the Palmers FC team, who have 200,000 followers - so the brothers decided to build something a bit different.
Inspired by EA video game franchise Fifa, they devised a tournament in which the team would play real matches within a fictional league, working their way from fifth to first division, where they are currently. They are promoted or relegated depending on a points system dictated by match wins - their current target is to reach 22 points in order to top their own first division.
This way, Hashtag United can choose their opponents, and include teams from other big YouTube channels like Copa90 and the F2Freestylers as well as sponsored teams.
It also secures occasional access to the big stadiums - sometimes through sponsored deals with, say, BT Sport, and sometimes because they play a team connected to a particularly hallowed arena. So, for example, a match against Arsenal community team Arsenal For All got them on to the pitch of the Emirates Stadium.
"He has always wanted to own his own football club," says Seb Carmichael-Brown, who is also Spencer's brother.
"But it's not viable for a 28-year-old YouTuber. So we thought, let's start his own."
"A lot of our games go out four to five weeks later. If we have a big crowd, they'll all have their phones, and the results will leak."
"We have recently thought about ways we might move towards a model where all the games are open," he said.