Aigner was born in Feldkirchen-Westerham, Bavaria, and entered Angela Merkel's grand coalition cabinet as Federal Minister of Food, Agriculture and Consumer Protection on 31 October 2008.

Aigner was a little-known member of parliament with no previous ministerial experience when she took over as Federal Minister for Consumer Protection, Food and Agriculture in the cabinet of Chancellor Angela Merkel in 2008,[4] replacing Horst Seehofer.

[6] In response, she imposed tough new safety standards for animal feed manufacturers, a move widely supported in the market to retain public confidence.

[7] In 2009, Aigner caused a controversy when she called for requirements to publish the names and location of recipients of Common Agricultural Policy (CAP) subsidies to be “suspended” until the implications for data protection have been assessed.

In 2010, she criticized Google over plans to give property owners a four-week deadline to stop their buildings from showing up on the company's then newly launched Street View mapping service, demanding that all requests be considered instead.

[14] Following her return to Bavaria after the state′s 2013 elections, Aigner was named Minister-President Horst Seehofer′s deputy as well as Bavarian Minister for Economic Affairs, Media, Energy and Technology.

In the negotiations to form a grand coalition following the 2013 national elections, Aigner led the CDU/CSU delegation in the working group on economic affairs; her co-chair from the SPD was Hubertus Heil.