[1] Hassan-Nahon is daughter of the late Chief Minister Sir Joshua Abraham Hassan and his second wife, Marcelle Bensimon, both Jews of Moroccan and Portuguese origin.
After the death of minister Charles Bruzon, Hassan Nahon announced her candidacy for the Gibraltar Social Democrats (GSD) in the by-election of 4 July 2013.
On 19 May 2016, she resigned from the Gibraltar Social Democrats, alluding to "toxic" tensions within the party;[5] she decided to continue as a member of the parliament, albeit as an independent.
[6] On 15 September 2016, during a heated exchange of words in Parliament, the Minister of Justice, Gilbert Licudi, swore at Hassan Nahon repeatedly while the microphone was off, but still clearly audible.
On election day, Marlene won the only seat for TG, unseating GSD's MP and Shadow Minister, Trevor Hammond, after serving only one term.