In 1901 George was indeed a professional footballer,lodging with the Eades family (as a single man) in Wolverhampton,possibly playing for Wolves? He must have then moved to Grimsby because his daughter from his 2nd marriage was born there.
1901
Eades Sarah E 44 Head Kidderminster, Worcestershire 207 Coleman Street, Wolverhampton Western
Eades William P 18 Son House Carpenter Bilston, Staffordshire
Eades Nellie 15 Daur Draper Assistant Birmingham, Warwickshire
Eades Thomas A 13 Son Commercial Clerk Quarry Bank, Staffordshire
Harper George 23 Boarder Professional Footballer (single) Birmingham, Warwickshire.
1911
HARPER, George Henry Head 33 Professional Footballer born 1878 Warwickshire Birmingham
Married 9 years
HARPER, May Evelyn Wife 29 born1882 Warwickshire Birmingham
HARPER, Dorothy May Daughter 8 born1903 Grimsby Lincolnshire
Address: 1 St Ives Place 1 Bk 245 Coventry Road Small Heath
He did indeed play for Wolves. Found the following mention of him in a cup tie replay against QPR January 1900
"It looked like it would ultimately prove to be the Londoner’s undoing as Wolves sprang to life shortly before the interval when they were reduced to ten men by the loss of George Harper to injury. It had looked doubtful that Harper would be fit to continue but a ten minute chance to recover at half time saw him emerge with his team mates for the second period. Wolves now began to really turn the screw as Trevor Own crashed a long range shot against Clutterbuck’s post before Harper was left holding his head in his hands when referee Kingscott stopped play for a foul on Bryan a second before Harper fired past Clutterbuck to seemingly break the deadlock. It had been a hasty decision by Kingscott, which would ultimately cost Wolves their place in the cup, though that wasn’t apparent yet. Then, ten minutes from time, it seemed that the ref was out to make amends when he awarded Wolves the softest of penalties. Ted Pheasant then stroked a tame spot kick wide of Clutterbuck’s goal and suddenly it seemed that the gods themselves were smiling on the Londoners." (source:freewebs.com)