His father was a farmer and merchant and his mother had half-siblings who were the grandchildren of Swiss educator, Johann Heinrich Pestalozzi.

[1] Jaeger was educated in public schools until the age of sixteen and then served an apprenticeship at a dry good store from 1860 to 1863.

When he was not grafting and propagating his hybrids, Jaeger could be found exploring the countryside in search of new wild grape species.

The eastern cuttings he used in his hybrids unintentionally introduced downy mildew, a potentially devastating blight on vineyards.

After the spectacular success of Missouri wines at the Vienna World Fair of 1851, taking 8 of the 12 medals on offer, the French responded by importing Norton / Cynthiana rootstocks from the US, and unwittingly introducing phylloxera, which then ravaged the vineyards of France, Spain, and Portugal during the 1870s.

[2] For all his success, Jaeger was to be beset by financial problems in the 1890s following the passing of a local law, many years ahead of Prohibition, banning the sale of alcohol in Newton County, Missouri.

[4] On 16 May 1895, Jaeger bade farewell to his wife and children, telling them he was returning to Neosho to address legal matters.

Written in German, it was translated and printed in the Newton County News on May 23:[5] "My Dear, Good Elise: When you read these lines, I won’t be no more alive.

Some thought he returned to Switzerland or started fresh in California but most felt that he was despondent over business and legal problems and killed himself.