The club was reformed in the Kingdom of Yugoslavia as SK Hermes in late 1918 and played in the Ljubljana Subassociation League from 1920 on, scoring best result with fourth place on four occasions.

They started quite well, but fell again in the spring period, specially with three defeats in last three rounds, which pushed them to final 10th place.

In their last season the club had struggled on the pitch and failed to obtain competition licences issued by the Football Association of Slovenia, which led to its dissolution in 2005.

After finishing 9th in the national championship, NK Ljubljana effectively ceased all operations, together with another two top division teams, Olimpija and Mura.

Rivalry, that attracted even 10,000 spectators to the matches between Železničar and Odred in the post-war years, has eventually faded in the following decades.

Rather neglected in the industrial Šiška, Ljubljana had some support in local workes, mostly residents from other Yugoslav republics.

First organized fan groups of Ljubljana were formed in the early 1990s, when the club was playing a major role in Slovenian league.

While the first kits used by Hermes were red and white, the club then adopted typical railway identity, using blue color through most of its history.

Although sometimes playing in all-blue, the team was nicknamed as Modro-beli (The Blue and Whites) and the club's logo used stripes as the railway symbol.

The fairly distinctive sky blue-white combination, used in those first league years, was later replaced by dark blue.