While his father was still active, Kronenberg managed the Saint Petersburg branch of the Warsaw Commercial Bank.

In 1887, however, he was obliged to resign, on account of his brother's illness, in order to look after the management of the railway lines in which the latter was interested and of the Commercial Bank of Warsaw.

He was president of the Society for the Mutual Help of Musical Artists, a working member of the Polytechnical Committee in Warsaw, etc.

In recognition of his distinguished services in connection with great commercial undertakings, he was made a hereditary baron of the Russian empire in 1893.

Shortly before his death, Leopold Kronenberg converted to Catholicism so that he could be buried next to his wife in the family vault at Warsaw's Powązki Cemetery.