First appearing on stage in 1970, and on screen two years later, Diaconu pursued a lengthy career in both formats, working with a series of prominent directors.

[1][3] Diaconu made his theatrical debut a year before finishing university, at the Bulandra Theater, in Truman Capote's The Grass Harp.

He spent the night outdoors with students, believing that, although the uprising lacked familiar leaders who could be trusted, the crowd at least recognized popular actors' faces.

During the night, Securitate secret police fired through apartment windows, while the next morning, Diaconu saw that agents had quietly killed people with brass knuckles.

However, he soon noticed that a revolution was in full swing, the boulevards leading to the city center packed with advancing workers who had trapped two tanks, one of which he rode to the Central Committee building from which Ceaușescu had spoken the previous day.

[8] Diaconu began his political career in 2008, when he was elected to the Senate for Argeș County as a member of the National Liberal Party (PNL).

[9] In May 2012, he was named Culture Minister in the new Victor Ponta cabinet,[1] but was forced out of office the following month when the High Court of Cassation and Justice ruled there was a conflict of interest between his ministerial position and his managerial role at the theater.

[11] In March 2014, when the PNL failed to include him on its list of candidates for that year's European Parliament election, Diaconu decided to run as an independent.

[13] He is thought to have significantly eroded the PNL vote, with one party member, Nicolae Robu, claiming Diaconu cut its performance by nearly half.

[18] His proposals included expanding the Cernavodă Nuclear Power Plant and salvaging the Rovinari Power Station; building and revitalizing Danube River ports and bridges, using European Union funds; unifying small landholdings into larger, more profitable farms; and a stricter approach to school discipline, such as banning mobile phones and reintroducing uniforms.

On foreign policy, he called for Romania to play a stronger role within the EU and NATO, while reaffirming the country's alliance with the United States.