After period of quiet during World War I, the two clubs re-united and joined the Athenian League in 1919, named Kingstonian.

At the same time the club also moved to a ground in Oil Mill Lane (modern day Villiers Road).

[3] At the club's annual general meeting in 1890, the secretary at the time, William G. Carn, proposed that the name became "one more identified with the town".

[3] The first competitive match in Kingston's history was in November 1893 and resulted in a loss, after a replayed game, to Hampton Court & East Molesey.

[3] The club re-entered the Surrey Junior Cup and in 1896 joined the Kingston & District League as founder members.

[3] By the start of World War One, Old Kingstonians held a definite supremacy of the two clubs, and in 1913–1914 won three trophies including the Southern Suburban League and Surrey Senior Cup.

Over the period of the split several appeals had been made by both clubs concerning eligibility of players in matches between the two sides, and in two cases the result of the game was overturned.

In the 1913–1914 season the Surrey Charity Shield match between the two clubs saw a number of incidents involving players and spectators and this led to the Surrey FA taking responsibility for the running of the replay with warning notices posted at the ground and a large police presence.

An FA enquiry into incidents at the first game led to one of the witnesses being attacked on their return to Kingston after giving evidence.

At the start of the 1911–1912 season Old Kingstonians also moved to the Southern Suburban League where both teams stayed until the outbreak of World War One.

The following season Kingstonian were successful in purchasing the Richmond Road ground, although the groundshare arrangement with Leyland Motors continued.

They had a more successful spell from 1923 up to the outbreak of World War II, winning the league in 1924, and in 1926 with a record number of points.

[3] "Competitive Amateur Football" was called off in September 1939 for World War II and Kingstonian were to play only one game at the start of the 1939/1940 season.

Depleted of the majority of their pre-war players, Kingstonian came last in the first league after the war in 1945–1946 season, and had to resort to fundraising to gather money to renovate both the stadium and the changing rooms.

[3] In the 1959–60 season, the Ks had their first Wembley Stadium appearance in the FA Amateur Cup final, which was lost to Hendon F.C.

Entering the competition at the Fourth Qualifying Round, they beat Devizes Town before beating two Football League clubs – Brentford[6] and Southend United,[7] either side of a win over fellow Conference team Southport – on their way to the FA Cup fourth round, where they were drawn with Bristol City[8] before succumbing to a late winner in the replay, losing 1–0.

[9][10] Relegation and, moreover, financial problems as a result of severe overspending in the chase for success,[citation needed] saw a sharp downturn in the club's fortunes between 2001 and 2005, and in 2003 the then manager Kim Harris said that the owner, property developer Rajesh Khosla, was "raping us" after Khosla sold the Kingsmeadow ground for £2 million in personal profit.

[11] However, in February 2005 Khosla stepped down as chairman, selling the club to Jimmy Cochrane,[12] whilst making a profit.

They only narrowly missed out on the promotion playoffs[13] and finished their season by beating AFC Wimbledon in the final of the Surrey Senior Cup at Woking's ground 1–0.

[14] Changes continued during mid-2006 with Mark Anderson and Malcolm Winwright taking charge of the club, installing Stuart McIntyre as successor to Ian McDonald in the role of head coach.

However, after the 2013–14 Isthmian League in which Kingstonian finished second but missed out on promotion, on 11 May 2014 Dowson resigned,[15] being replaced by Tommy Williams.

[16] With former Ks midfielder Tommy Williams installed as manager, the club again reached the FA Cup Third Qualifying Round, losing 3–2 to a last minute goal against Eastbourne Borough.

The league campaign saw the club make late challenge for the play-offs falling short in the last couple of weeks of the season.

Ks left the Kingsmeadow Stadium at the end of the season and moved to Fetcham Grove to groundshare with Leatherhead.

At the beginning of the 2018–19 season, Kingstonian moved back to the Royal Borough of Kingston upon Thames and started a ground share with Corinthian-Casuals at King George's Field.

A difficult season saw Ks have three managers, as Leigh Dynan was replaced by Dean Brennan and then very quickly by stand-in manager Kim Harris - the Ks moved from second place in the table on New Year's Day to escaping relegation by a single place.

The club managed to negotiate a ground-sharing arrangement and were eventually able to buy the land, but the issue impacted their performance.

Kingstonian secured a financially favourable 25-year sub-tenancy agreement with AFC Wimbledon, with customary break clauses.

Chelsea's intention was to use Kingsmeadow as a base for their own youth and women's teams, and were unwilling to accommodate Kingstonian.