Hymanson joins as co-head of the employment department, leading the group with Marian Derham.
He is the external lawyer of choice for Gillian Switalski, an ex-employee of F&C Asset Management who is claiming £19m compensation for workplace sex discrimination.
Hymanson’s practice focuses on board-level employment disputes in the leisure and media sectors.
Harbottle managing partner Glen Atchison said: “We have a well-respected employment practice that has gone from strength to strength in the past few years. Howard will further enhance our reputation in this area.”