after joining woolwich arsenal in may 1900, blackwood scored on his debut, in a 2–1 win over gainsborough trinity on the opening day of the 1900–01 season. this was to be his only season with the club; he scored six goals in 17 league appearances. he also scored during his one appearance in the fa cup, against darwen on 5 january 1901. he left for reading in may 1901.