But with a prolific academic and artistic background, Rahnavard is to many a household name in her own right, especially those who studied at Tehran's all-women Al-Zahra university, where she was chancellor for eight years. Since her husband announced his bid for the presidency, she has appeared at most of his campaign rallies and has given numerous speeches, notably criticising Iran's treatment of women, especially under hardline President Mahmoud Ahmadinejad.
"It is very ordinary, natural, sensible and religiously-accepted" for a president's wife to have an active and visible role alongside her husband, she said in an interview with popular youth weekly Chelcheragh this month.
The 64-year-old grandmother, whose husband served as Iran's last premier before the post was abolished in 1989, has said that mothering three daughters has made her more sensitive and concerned about women's issues.
Despite appearing in public in the traditional black chador favoured by conservative women, she sports flowery headscarves and bright coats underneath, and says she did not wear the Islamic veil until her early 20s.
The sculptor and painter says she enjoys rap music and her favourite accessory is a bohemian handbag adorned with Iranian tribal motifs.
In 1976, as the former regime stepped up its pressure on political dissent, Rahnavard left Iran for the United States with her two children and returned shortly before Islamic revolutionaries seized power in 1979.
She holds a PhD in political science and served as an advisor to Khatami, who was president from 1997 to 2005. She has also been a Koran researcher and authored several books on art and politics.
A picture of Rahnavard and Mousavi leaving a rally holding hands has been circulating in cyber space, sparking positive comments on many blogs -- although conservatives frown upon public displays of affection even between married couples in Iran.