Daughter of actors Raf Vallone and Elena Varzi, she made her film debut in 1979 in the "poliziottesco" Gardenia, later starred in several genre films, except for the more ambitious Alberto Bevilacqua's drama film Le rose di Danzica.
During his career Laimi worked to films of different genres, often united from having Milan as set, including Eriprando Visconti's film debut A Milanese Story, Duccio Tessari's noir film La morte risale a ieri sera, Umberto Lenzi's poliziottesco Gang War in Milan, Carlo Lizzani's Storie di vita e malavita and Renato Pozzetto's directorial debut Saxofone.