The 36-year-old, who played for the Gulls between 1994 and 1995, comes in as a replacement for sacked boss Leroy Rosenior.
Rosenior was recruited by the board shortly after their League Two campaign ended in relegation, but was sacked shortly after when a new regime took control.
Now, with non-League football looming, the club's new chief executive Colin Lee is hopeful a bright future is on the horizon.
He told the club's official website, www.torquayunited.co.uk: "We are delighted to have Paul onboard. I believe he will prove to be an outstanding managerial talent, someone who shares our core beliefs, values and work ethic."
Buckle added: "I am delighted and very proud to be given the opportunity to manage Torquay and am looking forward to working with everybody at the club as we begin a new era."