Siddall was promoted to the Tufts University Director of Rowing in the summer of 2026 after a unprecedented run as the head coach of the Tufts University women's rowing squad. The Jumbo women's program is currently in the midst of three straight NCAA Championships, while she takes over one of the top Division III men's rowing programs in the nation/ 

After guiding Tufts University Women's Rowing to its first-ever NCAA Division III Championship and first New England Small Athletic Conference (NESCAC) title last spring, head coach Lily Siddall received the Collegiate Rowing Coaches Association (CRCA) Division III National Coach of the Year award for the 2023-24 season. She would repeat that feat in 2025-26. 

Siddall had been promoted to interim women's rowing head coach in August 2023 when previous Director of Rowing and women's head coach Noel Wanner left Tufts for a position at Dartmouth College. In that role Siddall led the Jumbos to unprecedented success. In addition to winning the NCAA and NESCAC championships in the spring, the team also won the Collegiate Eights event at the prestigious Head of the Charles Regatta in the fall.

The 2023-24 Jumbos also won the Points Trophy at both the New England Rowing Championships and the National Invitational Rowing Championships (NIRC), emblematic of the depth and talent of the team. In addition to their success on the water, the team had 19 individuals earn NESCAC All-Academic Team honors for carrying grade point averages of 3.50 or better. Siddall was also recognized with CRCA New England Region and NESCAC Coach of the Year honors as well.

The Tufts University Department of Athletics removed Siddall's interim status over the summer of 2024. She is heading into her eighth season overall with the Jumbos in 2026-27, and fourth season as the head coach of the Tufts women's rowing squad. 

Siddall has been a key member of the Tufts women's rowing coaching staff since 2019-20. She was an assistant coach for the Jumbos' back-to-back NCAA Championship qualifying seasons of 2022 and 2023. The Jumbos finished sixth nationally in 2022, then moved up to third place at the NCAA competition in 2023. Tufts was also the only squad to medal in all races at the 2023 NIRC and won the team points trophy that year.

Prior to Tufts, Siddall was an assistant coach at the University of Massachusetts for the women's rowing team. Raised in Belmont, Mass., Carbeck graduated from Belmont High School and then from the UMass where she designed her own major in Youth Development and Coaching.