Magirus was the son of a grocer and factory owner and pursued commercial studies in Naples.
In 1850, Magirus took over his father's business and published his history of firefighting techniques, Das Feuerlöschwesen in allen seinen Theilen.
On July 10 of that same year, he was the principal founder of the Deutscher Feuerwehrverband, an association of professional firefighters, which still exists.
He soon put a second fire engine in operation and worked to improve the organization and technology of the fire-fighting process.
An annual prize, named after Magirus, is awarded to the "Best Fire Brigade Team of the Year" in Germany.