After finishing school, Rainer Bock managed a café in his hometown, where there was also a cabaret program. After studying acting at a private acting school in Kiel, he made his debut as a theater actor on the stages of the state capital Kiel in 1982. Through the Schleswig-Holstein State Theater he came to Heidelberg and the National Theater Mannheim. From 1995 to 2001 he was engaged at the Stuttgart State Theater. Until 2011 he was engaged at the Bavarian State Theater in Munich.

Bock often appears in supporting roles, including his initially rare appearances in film and on television. The role of the doctor in Michael Haneke's award-winning drama The White Ribbon — A German Children's Story (2009) earned him a nomination for the German Film Award. In 2011 he was presented at the Berlinale with four films. Bock is also active as an audiobook reader.