Mara began her career in 1967, as secretary in the Ariston Records press office, working with Ornella Vanoni and Mino Reitano. She is married with Alberto Salerno (son of Nicola Salerno, songwriter of hits like Torero, Tu vuò fà l'americano, Guaglione, Non ho l'età e Un ragazzo di strada) and has two daughters Giulia and Camilla, who are her press officer.
In 1969 she reached at the Numero Uno, record label founded by Mogol and Lucio Battisti. The experience with the pair of authors has direct her, in the 1970s, at the Dischi Ricordi, where she became a talent discoverer of singer like Gianna Nannini. Later, she becomes art director, following the musical path of Fabrizio De André e Mia Martini.
In the 1990s, she meets Tiziano Ferro in SanremoLab academy and produces his first three albums.
Completed the experience with the Nisa, she founds with the husband and the daughters the record label Non ho l'età, with the aim of promoting new musical talents.
In 2010, she was also in the fourth edition with three new judges: Elio, Enrico Ruggeri and Anna Tatangelo. She also released a dance single called Fantastic that peaked at #2 in the Italian Singles Chart. Was recently confirmed her participation at the talent show Amici di Maria De Filippi in 2011.
Maionchi did not return for the fifth edition of X Factor in 2011 and was replaced by Arisa.