The new role of vice president, global marketing and communications, will see Philalithes relocate from Miva's London office to its New York office.
She will report to chief marketing officer Seb Bishop and lead a global team of 20, as well as manage the company's appointed marketing and communications agencies.
Philalithes is a founding member of Miva, formerly known as Espotting.
After joining Espotting in 2000, she was promoted to UK marketing director in 2001 and then European marketing director in 2004.
Miva is the paid-for-performance search network, which formed last year after the merger of Espotting and FindWhat.com.