Career
Kinhöfer is appointed to matches under the auspices of the German FA since 1994. He was added to the list of 2nd Bundesliga referees in 1997 and promoted to Bundesliga status in 2002. In 2010, he officiated the Final of the DFB-Pokal.
Kinhöfer is on the Fédération internationale de football association eligible list since January 2006.
He was also appointed to matches of the South Korean K-League in 2003, the Qatar Stars League in 2006, 2007, 2008 and 2010 and the Saudi Professional League in 2008 as a guest referee. Kinhöfer lives in Herne and works as a Comptroller at the Municipal Utility District of the city.