After his graduation, he served his alternative civilian service at Baden-Württemberg State Institute for the Environment, Survey and Nature Conservation (LUBW) in Karlsruhe.

In December 2019, Lindner filed a criminal complaint over the erasure of data from a mobile phone owned by Ursula von der Leyen when she was Germany's defense minister, citing suspected deliberate destruction of evidence.

[6] In July 2024, Lindner announced that he would not stand in the 2025 federal elections but instead resign from active politics by the end of the parliamentary term.

[7] When German Defence Minister Thomas de Maizière cancelled the Euro Hawk surveillance drone program, one of the federal government's key defense projects, which failed because it was unable to fulfill the requirements necessary to be certified to fly in German airspace, Linder sharply criticized the government for "the biggest procurement disaster of the last 20 years.

"[8] Lindner called Germany's nuclear sharing agreement "an expensive, dangerous and antiquated symbolic contribution to have a say within NATO.