Education and career 
Borgström earned a law degree from Stockholm University in 1974. Thereafter he started to work as a lawyer. He has worked on several high-profile criminal cases, most notably as a defence counsel for convicted mass murderer Thomas Quick. With no technical evidence, Quick was convicted of eight out of the more than thirty murders he confessed to. Five of the convictions have been overturned. It has been questioned whether Borgström as Thomas Quick's attorney neglected to protect his mentally disturbed client's objective interest in being judged not guilty. Jan Guillou has described Borgström's 5 years as defense counsel of Thomas Quick as "the worst defense counsel job in modern Swedish history." 
Between 2000 and 2007, Borgström served the Swedish government as Equality Ombudsman (JämO). Borgström expressed his dislike of this job to his client Sture Bergwall. He described the job as boring and he would not stay for the full tenancy.
After the defeat of the Social Democrats in 2006, he resigned to start a law firm with former Social Democratic Minister of Justice Thomas Bodström as partner. Borgström himself had plans of becoming the Minister of Justice if the Social Democrats had won the election in 2010 according to his client Sture Bergwall. Claes said the following of the current Minister of Justice and his current partner: "I have no high thoughts of Thomas Bodström. It is actually unimaginable how the current Minister of Justice was chosen for his post. He is a shallow person."
Borgström has often attracted attention with his controversial behaviour. He claims that all men carry a collective responsibility for violence against women and has in this context supported Gudrun Schyman's "Tax on Men".
He also attracted attention in March 2006 when he demanded that Sweden boycott the 2006 World Cup in Germany "in protest against the increase in the trafficking in women that the event is expected to result in".
In 2010 Borgström successfully appealed the decision to close the sexual assault case against WikiLeaks founder Julian Assange, and became the legal representative of the two Swedish women who have accused Assange of sexual misconduct.
Personal life 
Borgström married his former colleague Märit Borgström (née Röger) in 2007. He has three children from an earlier marriage. He is the brother of journalists Annette Kullenberg and Kerstin Vinterhed.
- "Advokat Claes Borgström" (in Swedish). Borgström & Bodström advokatbyrå. Retrieved 31 August 2010.
- Borgström, Claes (15 April 2010). "Jag anmäler mig själv till advokatsamfundet". Dagens Nyheter (in Swedish). Retrieved 31 August 2010.
- "Quick fri för mord på norska kvinnor". Dagens Nyheter (in Swedish). 24 September 2012. Retrieved 24 September 2012.
- "Borgström svek Quick". Aftonbladet. 13 January 2006.
- "Hårda ord när Borgström mötte Guillou i debatt om Quick". Aftonbladet. 10 September 2012.
- Bergwall, Sture (8 October 2012). "PARENTES. Mitt sista samtal med Claes Borgström." (in Swedish). Retrieved 19 October 2010. Unknown parameter
- Sörbring, Gunnar (31 March 2007). "Claes Borgström slutar som JämO". Dagens Nyheter (in Swedish). Retrieved 31 August 2010.
- Olsson, Lova (8 April 2008). "Döm sexköpare till fängelsestraff". Svenska Dagbladet (in Swedish). Retrieved 31 August 2010.
- "Så ska vi hjälpa kvinnorna". Aftonbladet. 1 Nov 2004.
- Sida på JämOs webbplats
- Hosenball, Mark (25 August 2010). "Lawyer for Women Accusing WikiLeaks Founder Maintains Charges of Sexual Misconduct". Newsweek. Retrieved 7 December 2010.
- Mattsson, Åsa (4 July 2007). "Claes Borgström: "Jag spelade både fotboll och klippte klippdockor"". Salong K (in Swedish). Retrieved 8 December 2010.
- Thunberg, Karin (29 November 2009). "Jämt jämställd". Svenska Dagbladet (in Swedish). Retrieved 31 August 2010.
- (Swedish) Borgström accused of making inappropriately demeaning public statements about Julian Assange. Accessed 19 August 2012.
|Swedish Equality Ombudsman