Alt St. Johann has a population () of 1466. , about 9.4% of the population was made up of foreign nationals. Of the foreign population, (), 19 are from
Germany, 3 are from
Italy, 91 are from ex-
Yugoslavia, 8 are from
Austria, and 37 are from another country. Over the last 10 years the population has decreased at a rate of -3.9%. Most of the population () speaks German (93.0%), with Serbo-Croatian being second most common ( 3.3%) and Albanian being third ( 1.4%). Of the Swiss national languages (), 1,351 speak
German, 3 people speak French, and 3 people speak
Italian. there were 178 persons (or 12.3% of the population) who were living alone in a private dwelling. There were 273 (or 18.8%) persons who were part of a couple (married or otherwise committed) without children, and 832 (or 57.3%) who were part of a couple with children. There were 87 (or 6.0%) people who lived in single parent home, 2 persons who lived in a household made up of relatives, 5 who lived household made up of unrelated persons, and 76 who are either institutionalized or live in another type of collective housing. ==Heritage sites of national significance==