The club was founded in 1930, under the name of Park Modern Old Boys. In 1926 the Park Modern School in Barking was founded and the headmaster decided that the school would play rugby, despite football being the most popular sport in the area. As a result, the Old Boys team was created four years later and won 16 out of 19 games in its inaugural season.
Old Boys continued to prosper after the war. In 1974 they were declared no longer an Old Boys team, and so were obliged to change their name to Barking Park RFC, which became just Barking RFC in 1976.
Barking were successful upon the introduction of leagues and moved slowly up the league ladder. It is widely known that Jason Leonard, the most internationally capped prop in the history of rugby union began his club career at Barking. In 1989 Barking opened their current ground at Goresbrook, Dagenham and have remained there since. They reached the National Leagues in 1994. After winning National Division Three South in the 2004-05 season, Barking enjoyed two seasons in National Division Two before being relegated in 2007. The season began with a crushing 63-10 defeat at the hands of newly promoted Mounts Bay, who were eventually crowned champions. This set the tone for a season in which the Eastenders were constantly staving off the threat of relegation. However, Barking survived by the narrowest of margins after defeating the very team who had destroyed them on the opening day and finished the league as champions. The 16-14 win at Goresbrook was enough to send Bristol-based Clifton down by a single point and secure another season of National League rugby for Essex and London's East End.
Comedian and actor Nick Frost, known for his many film and television collaborations with Simon Pegg, is an ex-player.