Dowdy, whose career spans more than 40 years, was credited by Superintendent Eric Wright with a number of accomplishments during her four years with district, such as starting all-day pre-K, a phonics program and implementing virtual learning.
Sedillo was approved by the board during the May 17 meeting and will begin her new position July 1.
"I am excited that Marivel has accepted the challenge of leading our curriculum and instruction department," Wright said in a news release. "Her skill and experience in this area, combined with her knowledge of our district, our personnel and our students will make the transition smooth."
She was hired April 22, 2019, to be the district's chief of human resources but has more than 16 years of experience at HCISD.
She had previously worked as a teacher and principal for the district, and was the chief of human resources from 2001-06, according to HCISD's website.
Her career in education began in 1994 in Austin ISD where she taught bilingual special education.
“Ms. Sedillo brings to the district a broad base of experience at all levels of a school district," Wright said. "Her passion for students and staff members is amazing, and her leadership is impeccable."
Sedillo holds two bachelor's degrees from Southwest Texas State University, which is now known as Texas State University. She also earned a master's degree from Texas State and is pursuing a doctoral degree in educational leadership.
“Leaders in the education field often focus on managing expectations. As a leader, I see my role to inspire others to go beyond expectations,” Sedillo said. “I am honored to continue to serve Hays CISD students and teachers. This district is where I have spent the majority of my career, and this district is my home.”