The line has been extended multiple times. It initially ran between Pueblo Nuevo and Las Musas. On 17 May 1975, the line was extended from Pueblo Nuevo to Avenida de América, and was not extended for many years. This was a problem as line 7 was very underused. The problem was solved in 1998 and 1999 when an extension to Pitis was opened in four stages. The first stage was between Avenida de América and Gregorio Marañón, opening on 1 April 1998, followed by Gregorio Marañón to Canal. The next section to open extended the line to Valdezarza, and a final section further reached Pitis. Pitis, however, was the only station on the Madrid metro to have restricted opening times. At the time, Pitis was a very small village, and the station's main purpose is to provide interchange for Renfe services. Between 1999 and 2018, most trains ran between Estadio Olímpico and Lacoma, with Pitis being served by only a few trains each hour.
Beginning in 2019, all trains are expected to terminate at Pitis following the opening of Arroyofresno station, which was previously constructed, but not opened due to the ongoing construction of the surrounding developments. Arroyofresno station was finally opened on 23 March 2019.
On 4 May 2007, Line 7 was extended from Las Musas to the towns of Coslada and San Fernando. At Estadio Metropolitano, next to Atlético Madrid's Metropolitano Stadium, passengers have to change trains for MetroEste to Coslada and San Fernando - the so-called Line 7B.
The section of Line 7 between Estadio Metroplitano and Hospital del Henares, known as MetroEste or Line 7B, has been closed fully or partially several times since its opening in May 2007. San Fernando de Henares, which is close to the Jarama River, sits on a large salt deposit and is geologically composed of poorly suited soils. The drilling of the tunnel used for the extension has aggravated the high amount of groundwater-related subsidence in the area, making the area no longer suitable for new development; the tunnel has experienced repeated flooding and structural corrosion due to the subsidence. By the end of May 2023, the subsidence in San Fernando de Henares had destroyed numerous structures, forcing the relocation of a significant portion of the area's residents. On 24 August 2022, the section of Line 7B east of San Fernando station was closed for what would become a three-year period owing to reconstruction of the line's tunnels and remediation works; the closure would be extended to Barrio del Puerto station in July 2024. The entirety of Line 7B would fully reopen on 22 November 2025.
Rolling stock
Line 7A, the primary portion of the line from Pitis to Estadio Metropolitano, uses 6-car trains of class 9000. Line 7B, the extension to Hospital del Henares, uses 3-car trains of class 9000.