Allen has been head of Cognis' Strategic Business Unit (SBU) Functional Products since January 2006, and president of Cognis Corporation in the United States since February 2004. Previously, Allen held positions at several international companies before becoming European business manager of Diamond Shamrock Process Chemicals in 1985. After Henkel acquired this company, Allen took over as head of Henkel Canada in 1988. From 1991, he worked at Henkel Corporation (later Cognis Corporation) in the United States and was employed in a variety of posts.