It is the second fully automated and driverless rail system in the Klang Valley region after the LRT Kelana Jaya Line.

[5][6][7] In August 2006, the LRT Kota Damansara–Cheras line proposal was first made known to the public by the then Deputy Prime Minister Datuk Seri Najib Tun Razak under a RM10 billion government allocation for the improvement and expansion of the public transportation network in the Klang Valley as a new light rapid transit (LRT) system.

The line is also targeted to alleviate traffic congestion in the Klang Valley by encouraging more commuters to opt for public transport.

[note 2] It is also aimed to reduce overcrowding on the KL Monorail and to provide an alternative transport mode due to rising fuel prices.

[12] The line would be 40 km (25 mi) long, serving densely populated areas in Damansara and Cheras via "The Golden Triangle" of Kuala Lumpur city.

[9] In September 2008, Executive Director of SPNB said that a 5.9 km (3.7 mi) section of the line in central Kuala Lumpur will be underground, serving 5 stations.

The line was being considered for as a Mass Rapid Transit (MRT) system after taking into consideration the catchment area serving a population of 878,000.

[14][note 4] On 14 September 2009, SPNB managing director Datuk Idrose Mohamed was reported as saying that the new line could end up longer than the earlier announced alignment although he did not offer any further details.

SPNB has raised the necessary funds from Islamic investments of RM2 billion and hopes to gain approval from the Ministry of Transport to call out for tenders.

[21][22][note 7] The project, aimed to improve public transport in the Klang Valley, was approved by the Malaysian cabinet on 16 December 2010 and construction of the first line from Sungai Buloh to Kajang would begin in July 2011 with a duration of five to six years.

The final alignment was adjusted following the public display, having a length of 51 km (32 mi) with 31 stations where 16 have Park and Ride facilities.

[27] On 17 August 2011, the government announced that Mass Rapid Transit Corporation Sdn Bhd (MRT Corp), a new company under the Finance Ministry had been formed to take control of the project from Prasarana.

[28] After the MRT project was formally launched on 8 July 2011, the following amendments have been made to the original proposed alignment following the public display exercise between March and May 2011:[27][29] On 21 October 2011, MRT Corp shortlisted 5 companies to construct the underground parts of the line including MMC Gamuda Joint Venture and Sinohydro Group.

[40] On 1 November 2011, the 70's Klang bus stand ceased operations and was demolished to make way for the underground platforms and new entrances of Pasar Seni station.

[43] The shaft is 30 m (98 ft) deep and this TBM was to dig a distance of 1.2 km (0.75 mi) towards Pasar Rakyat (now Tun Razak Exchange) station.

[49] The MRT line covers a span of 47 kilometres (29 mi) from Kwasa Damansara to Kajang, passing the Kuala Lumpur city centre where the alignment goes underground.

[citation needed] The line serves a corridor with 1.2 million residents within the Klang Valley region from the northwest to the southeast of Kuala Lumpur.

[citation needed] The line continues in twin-bore tunnels underground to the Maluri portal, passing through the city centre and the Golden Triangle of Kuala Lumpur.

[citation needed] Interchanges to other lines are provided from Muzium Negara to Maluri with the exception of Cochrane station in Kuala Lumpur.

Muzium Negara is fitted with tiles that depict the transition of the city's mode of public transport while Pasar Seni is "painted" with 'Y's, which represents the convergence of the Klang and Gombak rivers.

Theme: Transition, History of Kuala Lumpur's Public Transportation Exit to NU Sentral via an underground walkway.

Pedestrian access to  KJ10  KLCC on the LRT Kelana Jaya Line and  MR7  Raja Chulan for the KL Monorail via an elevated walkway from Pavilion Kuala Lumpur.

Theme: Dynamic Exit to Lot 10, Sungei Wang Plaza, Fahrenheit 88, The Starhill and Pavilion Kuala Lumpur.

Feeder bus T402  to  SP13  Salak Selatan for the LRT Sri Petaling Line and Hospital Canselor Tuanku Muhriz UKM.

[54] Proposed interchange with Putrajaya Monorail According to MRT Corp, the four-car train sets are servicing the line with an average headway of 3.5 minutes in an hour, equivalent to 400,000 passengers per day.

[60] According to Transport Minister Anthony Loke, this is because the remaining fleet are awaiting wheel replacements, which is being carried out in stages from June 2022.