It was originally developed jointly by Bell Laboratories and Princeton University.

SML/NJ extends the SML'97 Basis Library with several added top-level structures:[3] Also, SML/NJ provides some syntactic constructs that are not standard features of SML'97:[3] Successor ML is a term used to describe the next version of the language.

[12] Since at least 1998,[13] MLton[14] is the standard bootstrapping compiler, and includes some[15] support for Successor ML.

[17] As of 2018[update], HaMLet remains the only complete implementation of Successor ML, with added novel features.

[15] Since 2015,[18] the evolution of SML/NJ geared towards evolving the Basis library[19] and adding support for the Successor ML definition with the release of version 110.79.