Mr Clarke, whose iwi are Waikato and Ngati Hine, is the Taikura Trust Operations excellence manager.
He was appointed to the position, which attracts a salary of between $130,000 and $150,000, ahead of six other applicants after the job was advertised for a second time a few months ago.
Announcing the appointment, the board said Mr Clarke brought leadership from an army, police and health sector background and he had previously worked in the Otago Southland region.
His appointment completes the board's regional executive management team.
He takes up his position in mid-January.
The board also announced the recent appointment of David Tulloch to the role of Southland's chief medical officer (CMO).
Mr Tulloch, who took on his new role late last month, is originally from the United Kingdom and came to New Zealand in 2006 to work at Southland Hospital as an urologist. He was he medical director of the surgical directorate at Southland Hospital.
He also has a private urology practice.
The board said Mr Tulloch would have an operational focus on Southland Hospital and Lakes District Hospital, at Frankton, but would also have a regional strategic responsibility within the board.
He will continue to work part of his time as a Southland-based clinician but will travel to Dunedin regularly.
Mr Tulloch took over from acting CMO Murray Fosbender who took on the interim role this year after the earlier departure of Dr Pim Allen.
Otago also has a CMO, Richard Bunton, who is based at Dunedin Hospital.
