Mr. von Hammerstein managed the architectural firm Architekturbüro Libeskind from 1989 until 1992 and in that context the planning of the Jewish Museum in Berlin. Starting in 1992, in his position as project manager at VITERRA, he realized the construction of the Indian embassy and several office buildings, among others, headquarters for EON AG. From 2003 until 2006 he was in charge of project management at HOCHTIEF Projectentwicklung Nordost. The office high rise RONDO ONZ in Warsaw, the OpernCarrée at Gendarmenmarkt in Berlin with, among others, the 5-star hotel de Rome, the Köbis Dreieick in Berlin with high quality residential space, and the headquarters of KPMG were realized in this time period. Subsequently, commissioned by the bank M.M.Warburg, he planned and managed the conversion of a landmarked palais into the new headquarters of Löbbecke bank.

In 2008 he founded westend consult and since then has been active on behalf of notable investors in Germany and abroad.