Winberg did his clerkship from 1960 to 1962 and worked as an extra legal clerk (fiskal) at the Court of Appeal for Southern Norrland in 1963.
Winberg worked in the steering group for the review of legislation on organized and economic crime from 1977 to 1979.
Furthermore, Winberg was a member of the Election Review Board (Valprövningsnämnden) from 1982, member of the Parliamentary Commission following the assassination of Olof Palme from 1987 to 1988, of the commission for further investigation of the investigation into the assassination of Olof Palme from 1994, member of the Swedish Security Service Committee (Säpokommittén) from 1989 to 1990, of the Court Inquiry (Domstolsutredningen) from 1990 to 1992, of the Cabinet Minister's Wages Inquiry (Statsrådslöneutredningen) from 1992 to 1993 and the JAS Commission from 1993 to 1994.
[1] Winberg wrote political and legal articles in Svenska Dagbladet, Svensk tidskrift, Medborgaren etc.
[1] In 1957, he married lawyer Ulla Greta Winberg (born 1933), the daughter of Johan Pettersson and Astrid (née Jönsson).