Idil Üner was born August 1, 1971, in Berlin, to Turkish parents. After finishing school, she started acting at a Turkish theatre in Berlin-Kreuzberg (where she later also directed plays), and studied acting at Berlin's Hochschule der Künste (HdK) from 1992 to 1996. While still at drama school, Üner was discovered by director Matti Geschonneck and played a role in the TV movie "Die Sache Baryschna" (1994), an episode of the popular "Tatort" series.

One year later, Üner made her debut on the big screen with a leading role in Rudolf Thome's "Das Geheimnis" (1995). She then received much attention for her portrayal of the sister of one of the protagonists in Fatih Akin's highly praised drama "Kurz und schmerzlos" ("Short Sharp Shock", 1998). In the same year, she also left an impression in the socio-critical immigrant story "Aprilkinder" ("April Children") by Yüksel Yavuz.

In 2000, Üner made another film with Akin whom she had already met in 1995 at a production for educational television. In the romantic road movie "Im Juli" ("In July"), she played the woman of the protagonist's (Moritz Bleibtreu) dreams.

In 2001, Idil Üner made her debut as a director with "Die Liebenden vom Hotel von Osman". The romantic short film, that features Üner and Fatih Akin in the leading roles, won the German short film award in Gold. Among Üner's most important roles are the leading roles in Thomas Arslan's drama "Dealer" (1999), in Dror Zahavi's comedy "Zwei Mädels auf Mallorca" (2000) and in Sülbiye V. Günar's TV-drama "Saniyes Lust" (2004), as well as bigger supporting roles in Sandra Nettelbeck's box office success "Bella Martha" ("Mostly Martha") and in Ralf Huettner's comedy "Reine Formsache" (2006).

In 2008 Idil Üner played in the comedy "Evet, ich will!" alongside Oliver Korittke. She had a recurring role in the acclaimed crime series "KDD – Kriminaldauerdienst", and also became a regular on the crime series "Mordkommission Istanbul" ("Homicide Unit Istanbul"). Moreover, she had guest roles in several episodes of the "Tatort" series and appeared in the TV productions "Lena Fauch und die Tochter des Amokläufers" (2012) and "Der große Schwindel" (2013). Ünel then returned to the big screen with a leading role in Buket Alakuş' culture-clash comedy "Einmal Hans mit scharfer Soße" which was released in June 2014.

In the following years, Üner again appeared in individual series guest roles, including one episode each of "SOKO Stuttgart" (2017), "Großstadtrevier" (2018), "Morden im Norden" (2019) and "Marie Brand" (2020). In 2018, she also had a recurring role in the RTL hospital series "Lifelines."  

Again directed by Buket Alakuş', a year earlier she played a supporting role as the mother of the main character in the turbulent TV comedy about the many facets of German welcome culture, "Eine Braut kommt selten allein." On the big screen, she was then seen in a supporting role in Sherry Hormann's docudrama "Nur eine Frau" ("A Regular Woman"), about the German-Kurdish Berliner Hatun Sürücü, who was murdered by one of her brothers because of her supposedly too "Western" lifestyle. The TV movie "Plötzlich so still," which premiered at the Filmfest Hamburg in September 2020, is also dedicated to a difficult subject, sudden infant death syndrome. The drama was first broadcast on ZDF in March 2021.  

In addition, Üner continued to appear as a regular in the crime series "Mordkommission Istanbul".