A 1976-batch Uttarakhand cadre IPS officer, Joshi was serving as the Special DG of CRPF at its headquarters here before his appointment as NSG DG.
Joshi, who had earlier served as the DGP of Uttarakhand, succeeds earlier R K Medhekar, who retired on April 30, as NSG chief.
Joshi will serve as the NSG chief till February 2014.
The NSG, which undertakes special counter-terror and counter-hijack operations, has expanded its base to major cities like Mumbai, Hyderabad, Kolkata and Chennai for quick response during emergencies.