Itchaya was born in Chiang Mai, Thailand, on August 6, 1958 [this is based on later, more accurate, information than she had at the time of the interview, so the date and place is different from that in the interview]. Her surname during her childhood was Supasri. She studied at Praruthai Catholic School from the fifth to the tenth grade and there began to develop a belief in God. However, her foster parents were Buddhist and were opposed to her belief. After graduation with a junior college degree from Chiang Mai Teachers College, she taught at the Regina Catholic School for one year.

In 1977, Itchaya began work as an announcer for the Thai Government Television Station in Lampang. Shortly after, she also became an announcer for the associated radio station. After a year, she moved back to Chiang Mai to work as an announcer for the Thai Army Radio Station. In addition to working many hours at the radio station, she began work for a B.A. from Payap University. During her last year of studies, Rev. Allan and Joan Eubanks came to a class and answered questions about Christianity, at which point she remembered her early faith. It was two years, however, before she sought out the Eubanks and committed herself to Christ. She began to study the Bible, was baptized, and became a member of the First Church of Chiang Mai.

In 1983, she began work with the Christian Communications Institute of Payap University, where she worked in folk drama, television, music, and evangelism, and also initiated the radio department and worked as Public Relations Officer. At the beginning of her work with the C.C.I., she met Manop Suriyakam, musician and evangelist on the C.C.I. team, and they were married three months later. They were later divorced.

Itchaya came to the United States in 1987 to work on an M.A. degree from Wheaton College, Wheaton, Illinois. She received her degree in 1989 and then returned to Thailand to continue work for Payap University where she founded the new communications department. She eventually became Vice President of Academic Affairs at the University. She took two years off (1996-1998) to go to the Philippines to earn a doctorate in Development Communications from the University of the Philippines at Los Banos. Also in 1998 she married Rev. William Sitterley, who was on the staff of Habitat for Humanity International. Itchaya also served on the National Board in Thailand of the Christian Broadcasting Network (CBN) and hosted on the network television shows. She also served on the board of the Voice of Peace, a Thai Christian radio program.