Michael Thamm began his career at Deutsche Seereederei (DSR) in 1985, helping establish the AIDA cruise brand, and remained with the business through its 1999 sale to P&O Princess Cruises. After Carnival Corporation's 2003 acquisition of P&O Princess, he became CEO of AIDA in June 2004.
He succeeded Pier Luigi Foschi as CEO of Costa Crociere on 1 July 2012, overseeing the AIDA, Costa Crociere and Ibero Cruceros brands, and coordinated the company's response to the Costa Concordia disaster that year. He also became CEO of Carnival Asia in January 2017, was elected chairman of CLIA Europe in 2019, and stepped down as CEO in April 2023.
In 2015, while CEO of Costa Crociere, he spoke as a panellist at the 11th Mare Forum Italy; in 2013 he appeared at the 9th Mare Forum Italy.