Humberside Police, said Darren Lee Barton was assaulted outside the Rutland Arms on Saturday.
He was taken to the Diana Princess of Wales Hospital in Grimsby after the incident at about 18:00 BST, but died on Wednesday evening.
Nathan Newland, 27, appeared before Grimsby and Cleethorpes Magistrates' Court on Tuesday charged with section 20 wounding and producing cannabis.
He was remanded in custody until 22 August when he is due to appear at Grimsby Crown Court.
Police said a post-mortem examination had yet to take place to establish the cause of death.
A 46-year-old man has died after he was attacked outside a pub in Grimsby.