Chris Millsback joined the St. Mark’s Mathematics Department after spending the last 19 years teaching math, as well as coaching baseball and football, at Sacramento Country Day School in California. Prior to that, Chris also taught at Lawrence Academy and Brewster Academy. Chris has a BA in Economics and Sociology from Wesleyan University, where he was also captain of the football team and an infielder on the baseball team. Chris enjoys teaching, being an advisor, and coaching football and baseball at St. Mark’s. Chris lives off campus with his wife, and children.

Nathan Argueta is the Assistant Director of Financial Aid and Associate Director of Admission. Nathan is coming from his alma mater Nativity Preparatory School New Bedford where he has served as the Dean of Instruction for the past two years. In this role, he prioritized re-envisioning the school's curriculum and instructional coaching & development as a means of pushing the school towards becoming an anti-racist institution. Nathan earned a Bachelor of Arts in English (with a minor in Film and Media Studies) from Davidson College. He has also served as the Assistant Director of Admission at New Hampton School. Nathan helps St. Mark's fill the halls with a diverse student-body committed to leadership and service. Nathan lives on campus, and in his free time, he enjoys going on long runs and salivating over sneaker-drops he'll never actually win.