In July 2017, he became chairman of the board of directors of Deutsche Apotheker- und Ärztebank which is a bank specialised on physicians and pharmacists in Germany as customers.

The assembly of the World Medical Association on 25 April 2019 at Santiago de Chile elected him as chairman of the board for two years.

[2][3] Montgomery was born in Hamburg to a British father who came to Germany during World War II as a military officer, and a German mother who was a physician.

Some 3,000 physicians had received gifts or money for prescribing Ratiopharm medical products, and an investigation had been launched in the city of Ulm because of multiple suspicions of fraud and breach of trust.

Montgomery called the business practices of physicians who had prescribed Ratiopharm products a "totally normal and natural behaviour", which could not be considered punishable.

[13] While the Ulm prosecutor found that the first two physicians involved in the issue had been bribed by Ratiopharm with a total amount of EUR 19,180, the investigation was closed in 2013 due to a lack of criminally relevant cases.

[16] Montgomery commented that the court had chosen the right path, but then also stated that no physician in Germany was allowed to accept gifts from pharmaceutical companies.

[20] Montgomery was blamed for acting dangerously by creating doubts about the mandatory wearing of facial covers in Germany during the pandemic.