He was leader of the United Democratic Forces (SDS) in from August 1990 to 4 December 1990 (heading the second-largest political party at the time).

[1] From 1963 up to 1969 he worked as a biologist at the Institute of Zoology with the Bulgarian Academy of Sciences, becoming a research fellow between 1969 and 1978.

[1] Beron was a founding member and secretary of the SDS (a coalition of multiple opposition groups) when it was formed on 7 December 1989.

In the January 1992 presidential elections Beron was the running mate of George Ganchev - leader of the Bulgarian Business Bloc.

Beron ran for president in 2001 with Stoyan Andreev (from the Bulgarian Union) as his running mate.