After I found the district head officers reassignments of Surat Thani, I tried to look further to find a more complete list. I found a complete list of district head officers as of October 2009, and also two lists of the most recent rounds of reassignments, one in August 2009 and another in February 2010. However strangely both not on the sites of the Ministry of Interior, the August 2090 list was in a gun lover forum, and even more strange the February 2010 list at an insurance company and only available in the Google cache.
As the district Galyani Vadhana was just created in December, only the second list could include a head officer for this district. According to this list, on February 22 2010, Chatthanat Thiankao (ฉัทธนาตย์ เทียนขาว) became the first full head district officer, replacing the acting district officer (รักษาราชการนายอำเภอ) Khunwat Sukhanthakun (คุณวัฒน์ สุคันธะกุล). While I cannot find any full biography of him, I can list the last two positions he held before he became assigned to Galyani Vadhana district. From August 2009 to February 2010 he was in Doi Luang, Chiang Rai province, and before that in Nong Hin, Sisaket province.