The chair of the Police Academy's centre for research and social skills, Šumi is an associate professor at the University of Maribor and has a PhD on ethics in for-profit and non-profit organisations.
He has served as expert in institutions such as the Council of Europe, Group of States against Corruption (GRECO), the European Police College (CEPOL), Frontex, the Geneva Centre for Security Sector Governance (DCAF) and the Organization for Security and Co-operation in Europe (OSCE).
Šumi "fulfils the high professional standards to successfully execute the duties of this office," the president's office said on Thursday.
"I wish that you perform your job to the best of your abilities and that by successfully preventing corruption you restore trust in integrity," Pahor told Šumi in a video the president's office posted on Twitter.
Šumi said he would give it his best. "I am confident success will be forthcoming."
In his public presentation earlier this week, Šumi underlined the importance of prevention, awareness and integrity, arguing that professionalism of the commission will be key in restoring people's trust.
He believes cooperation with a variety of players and institutions is vital for the commission and that awareness about corruption must be raised among people, boosting integrity.
Šumi was one of four candidates short-listed for the job by a vetting commission to replace outgoing commission president Boris Štefanec, who sought a second term but was snubbed for the job, having faced years of heavy criticism about his handling of the job.
The criticism focused on public conflict with staff and disingenuous handling of several major cases, which is seen as having hurt the watchdog's reputation.
Many believe this undermined the public's trust in the commission, as reflected in the number of reported cases of suspected corruption, which dropped from almost 1,500 in 2014 to just 541 last year.