Timchenko was born in Moscow on May 8, 1962. She graduated from the 3rd Moscow Medical Institute. From 1997 to 1999, she worked as an editor at the "Kommersant" newspaper. In 1999 she moved to the newly created online edition Lenta.ru, having risen from the monitoring officer to chief editor. In 2004, she assumed the position of editor in chief.

In 2010, Harvard University conducted a study of the Russian blogosphere, and recognized "Lenta.ru" as the most widely quoted in the Russian-language blogs news source. According to research firm comScore, conducted in April 2013, the site Lenta.ru took 5th place in attendance of European news sites. According to Alexa.com on March 2014 Lenta.ru ranked 16th most popular in Russia.

On March 12, 2014 the owner, Alexander Mamut, fired Galina Timchenko and replaced her with Alexey Goreslavsky. 39 employees out of the total 84, including Director-general Yuliya Minder, including 32 correspondents, all photo-editors (5 people) and 6 administrators.

The employees of Lenta.ru issued a statement that the purpose of the move was to install a new Editor-in-Chief directly controlled by the Kremlin and turn the website into a propaganda tool. In October 2014, Timchenko together with several former journalists of "Lenta.ru" launched a new media based in Riga, named Meduza. Timchenko told Forbes that the decision to base Meduza in Latvia was made because "it is possible to establish an independent publishing house in Latvia, while in Russia it is impossible."

Editing, Writer and editor Journalism, Russian, Russian Speaking,