Army United represent the Royal Thai Army and have traditionally been Thailand's yo-yo club along with the Navy and Police clubs. Up until 2010 and the name change from the Royal Thai Army to Army United, the club lacked support and had dwindling crowds, mainly supported by Army personnel shipped in for the games.

The Army team has always been a mid ranking Thai team with their biggest successes coming in the Thai Division 1 League with a championship in the 2004-05 season and 2nd place in 2009. Both of these successes have of course come after relegation from the TPL.

In the 2010 season they were reprieved from relegation after an end of season relegation/playoff system was announced to expand the TPL. They came 16th in that season and in a normal season they would have been relegated.

The club are based in the Din Daeng District of Central Bangkok, which is the area that bases the Royal Thai Army. Up until the 2011 season, the club operated a policy of only playing home grown talent, but ditched this as the game became more professional and foreign players were brought into the team. Previously the players would work for the Army during the week and play football on weekends, somewhat different to most clubs who operated on a full-time basis.