Bruno Mahlknecht attended the teacher education college in Merano and then worked as a primary school teacher in several places in South Tyrol, most recently in Bolzano-Gries. He later gave up his profession and devoted himself more to researching his homeland and writing.

As early as 1961, he began publishing local history articles in the South Tyrolean daily newspaper Dolomiten. He published in this newspaper for 40 years. From 1967 he also published in the local history magazine Der Schlern as well as in other periodicals. By 2012, he had written around 600 essays and articles on local history and culture. He has published several books since 1969. From 1979 to 1994 he was editor of the monthly magazine Tiroler Volkskultur (now "KulturFenster"), and since 1979 he has been editor of the South Tyrolean House Calendar. He worked for several years on local history programmes on Rai Südtirol radio, most recently from 2000 to 2006 on the programme Unser Land. In 2001/02, Mahlknecht published two articles in which he suggested the renaming of several Bolzano street names in the sense of restoring old Bolzano street names, which led to fierce attacks from Italian local newspapers.

Bruno Mahlknecht is married and has three children.