Born in Alba (near Cuneo) on 25 July 1957, he graduated in Law from the University of Turin in 1981.

A lawyer specializing in administrative law, he began his career working for the law firm of Professor Marco Siniscalco (eventually becoming a partner in the Siniscalco – Montanaro law firm in 2003) and, from 2003, he became main partner in the Montanaro & Associates law firm.

He has also worked extensively as a teacher: he taught Environmental Law at the University of Turin in 1997/1998; the Environmental Expert Master Course at the Turin Company Administration School in 1998/1999; Environmental Law at Eastern Piedmont University (Alessandria Faculty of Law) from 1998 to 2003; the Environmental Law Post-Graduate Specialization Course (now a Master) at the Alessandria Faculty of Law from 1998 to 2004; the Environmental Law Course at the Turin Polytechnic from 2000 to 2004 and at the University of Turin (Faculty of Law, from 2003 to 2004).

Montanaro also speaks at conventions pertaining administrative and environmental law problems and is a member of the "Ambiente e Sviluppo" (Environment and Development) scientific committee.