Line A was inaugurated on August 12, 1991 by Carlos Salinas de Gortari, President of Mexico from 1988 to 1994, Manuel Camacho Solís, Head of the Federal District Department from 1988 to 1993, and Ignacio Pichardo Pagaza, Governor of the State of Mexico from 1989 to 1993.

[3][4] Another feeder line, also connecting the State of Mexico to Mexico City, would be inaugurated in 1999: Line B, also using a letter instead of a number to designate it.

A proposed extension of the line was presented in 2018 by the Sistema de Transporte Colectivo.

According to the plan, Line A would be expanded southbound towards Chalco in the State of Mexico.

Currently, out of the 390 trains in the Mexico City Metro network, 17 are in service in Line A.