Theodor Klem won two bronze medals in the coxed fours at Olympic Games. At Stockholm in 1912, the Christiana outriggers boat beat Austria (Leitmeritz) by abandonment in the first round and the Belgian boat from Gand in the second. In the semi-final, they narrowly lost to the eventual silver medallists from the Thames Rowing Club. Klem returned in 1920 claiming another bronze. They beat Belgium in the heat and placed third in the final, losing to Switzerland and the United States.
Klem graduated in 1913 from the Technical School in Kristiania. For some years, he worked for Norsk Hydro, at the time a fertilizer producer. From 1923-29, he was a stage technician at Oslo’s National Theatre. Later, he was employed by a building engineering consultant. In 1923, he married his wife Ragnhild (née Foss).