Karimi started his career at the age of 14 in Padideh Sari. He then left the club after a year and trained with a personal trainer for two years before joining Esteghlal in 2012. During the 2012–13 season, he was part of Esteghlal U17 side and managed to finish the season as the top scorer of the Iranian U17 league. Karimi then joined Esteghlal reserve the next season where he finished as the top scorer once more. He also scored two goals against Persepolis reserve in the Under 21 derby on 3 January 2015.
After missing the first half of the season due to injury, he returned to action for the Hazfi Cup match against Iranjavan coming on as a 68th-minute substitute for Farshid Esmaeili. On 25 December 2017, he scored a hat-trick for Esteghlal in a 4–0 win against Sanat Naft.