[1] He played football for Baillieston Thistle, Clitheroe and Sheffield[1] before signing for Southern League club Reading in 1896.
[4] In the absence of Allan Hardy, he went straight into the team for the league match against Sheffield United on 13 April, which finished as a 3–3 draw.
[5] Hardy's return for the visit of Derby County "materially strengthened" the team, according to the Blackburn Standard, whose reporter thought O'Brien had been "of little use" the day before.
[7] For his next club, Swindon Town, he played in all five FA Cup ties and all but one Southern League fixture in 1902–03.
[8] He spent the folliwng season back with Reading, before joining another Southern League club, Brighton & Hove Albion, for 1904–05.