Ramsauer joined the conservative Young Union (JU) youth organisation in 1972 and the CSU in 1973.
He was elected Bavarian vice-chairman of the JU in 1983 and vice-chairman of the CSU in 2008.

In 1978 Ramsauer obtained a seat in the municipal diet (Stadtrat) of Traunreut and in 1984 became a member of the district assembly of Traunstein.

Ramsauer ran successfully in the 1990 federal election and has been a member of the Bundestag parliament since then.
From 1998 to 2005 he served as CSU Chief Whip of the CDU/CSU parliamentary group.
As such, he was also a member of the parliament's Council of Elders, which – among other duties – determines daily legislative agenda items and assigning committee chairpersons based on party representation.

Ramsauer was elected to the head of the Bundestag group of CSU parliamentarians in 2005, succeeding Michael Glos; in that capacity, he led the CDU/CSU parliamentary group with his co-chair from the CDU, Volker Kauder.
From 2005 until 2009, he also served on the Committee on the Election of Judges (Wahlausschuss), which is in charge of appointing judges to the Federal Constitutional Court of Germany.
In the 2009 elections Ramsauer was re-elected by 54.6 percent of the votes cast.

On 28 October 2009 Ramsauer was appointed Federal Minister of Transport, Building and Urban Development at the behest of Chancellor Angela Merkel, succeeding Wolfgang Tiefensee.
On the occasion of the sixtieth anniversary of the diplomatic relations between German and India, he participated in the first joint cabinet meeting of the two countries’ governments in Delhi in May 2011.

Since the 2013 elections, Ramsauer has been serving as chairman of the Committee on Economic Affairs and Energy as chairman.
In the negotiations to form another coalition government under the leadership of Merkel following the 2017 federal elections, he was part of the working group on economic policy, led by Thomas Strobl, Alexander Dobrindt and Brigitte Zypries.
He has since been serving on the Committee on Economic Cooperation and Development.

In early 2020, Ramsauer co-founded an informal cross-party group of MPs from the CDU, CSU and FDP parties who opposed a potential coalition government between CDU/CSU and the Green Party.
Ramsauer joined the conservative Young Union (JU) youth organisation in 1972 and the CSU in 1973. He was elected Bavarian vice-chairman of the JU in 1983 and vice-chairman of the CSU in 2008.
In 1978 Ramsauer obtained a seat in the municipal diet (Stadtrat) of Traunreut and in 1984 became a member of the district assembly of Traunstein.
Ramsauer ran successfully in the 1990 federal election and has been a member of the Bundestag parliament since then. From 1998 to 2005 he served as CSU Chief Whip of the CDU/CSU parliamentary group. As such, he was also a member of the parliament's Council of Elders, which – among other duties – determines daily legislative agenda items and assigning committee chairpersons based on party representation.
Ramsauer was elected to the head of the Bundestag group of CSU parliamentarians in 2005, succeeding Michael Glos; in that capacity, he led the CDU/CSU parliamentary group with his co-chair from the CDU, Volker Kauder. From 2005 until 2009, he also served on the Committee on the Election of Judges (Wahlausschuss), which is in charge of appointing judges to the Federal Constitutional Court of Germany.In the 2009 elections Ramsauer was re-elected by 54.6 percent of the votes cast.
On 28 October 2009 Ramsauer was appointed Federal Minister of Transport, Building and Urban Development at the behest of Chancellor Angela Merkel, succeeding Wolfgang Tiefensee. On the occasion of the sixtieth anniversary of the diplomatic relations between German and India, he participated in the first joint cabinet meeting of the two countries’ governments in Delhi in May 2011.
Since the 2013 elections, Ramsauer has been serving as chairman of the Committee on Economic Affairs and Energy as chairman. In the negotiations to form another coalition government under the leadership of Merkel following the 2017 federal elections, he was part of the working group on economic policy, led by Thomas Strobl, Alexander Dobrindt and Brigitte Zypries. He has since been serving on the Committee on Economic Cooperation and Development.
In early 2020, Ramsauer co-founded an informal cross-party group of MPs from the CDU, CSU and FDP parties who opposed a potential coalition government between CDU/CSU and the Green Party.
Peter Ramsauer