In 1992, Reiche was one of the founding members of the Ring Christlich-Demokratischer Studenten (Association of Christian-Democrat Students, RCDS) in Potsdam and in the same year she joined the Junge Union.

During the election campaign in 2002, Reiche was conscripted into the CDU/CSU's competence team by then chancellor candidate Edmund Stoiber, as an expert on women, youth and family policies.

In the negotiations to form a coalition government following the 2009 federal elections, Reiche was part of the working group on the environment, agriculture and consumer protection, led by Ilse Aigner and Michael Kauch.

[2] In the government of Chancellor Angela Merkel, Reiche first served as Parliamentary State Secretary at the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety under successive ministers Norbert Röttgen (2009-2012) and Peter Altmaier (2012-2013) from 2009 to 2013.

On the occasion of the sixtieth anniversary of the diplomatic relations between German and India, Reiche participated in the first joint cabinet meeting of the two countries' governments in Delhi in May 2011.