Grubb came through the academy at Weston-super-Mare, and worked as a sports teacher during a nine-year stay with the "Seagulls". On 5 December 2017, he signed an 18-month contract with EFL League Two side Forest Green Rovers after scoring 29 goals during the calendar year of 2017; the transfer was confirmed for an undisclosed fee on 1 January.[3] He moved on loan to Eastleigh in February 2020.[4] He left Forest Green Rovers at the end of the 2019–20 season following the expiry of his contract.[5] He returned to Weston-super-Mare in August 2020.[6] In May 2024, he joined Gloucester City.[7]