 He made his first-class debut for Oxford against Lancashire at the Christ Church ground in May 1907, taking the single wicket of Harry Dean.A little later in the summer, he took what was to remain a career-best innings haul of 8–48 against Marylebone Cricket Club (MCC) at The University Parks.Gilbert maintained his place in the Oxford side throughout that and the following two seasons, winning his Blue in each year and topping Oxford's bowling averages in 1908 and 1909.