In 1908, at the age of 21, McGuinness arrived in San Sebastián, where he taught English to Pedro Bea, the goalkeeper of the newly founded Club Ciclista.

[3] However, he was injured during that game, and even though Club Ciclista managed to hold on to the win with just nine men, the concern was whether their star would be able to play the final two days later at Campo de O'Donnell.

He left the San Sebastián entity at 23 to return to England, where he was a teacher at St Laurence's Roman Catholic School in Birkenhead – a town in the county of Merseyside near Liverpool.

Fourteen months later, on 7 November 1915, McGuinness (service number 16665) and his battalion crossed the English Channel to France aboard the SS Invicta.

Two weeks later, Edward and Catherine McGuinness received a letter at their home: John Caulfield, George's battalion mate, reported his death in combat by a bullet.