On 11 March 2007, he won a Harty Cup medal after lining out in goal for De La Salle's 2-07 to 0-11 defeat of St. Flannan's College.
[1] O'Keeffe retained his position in goal when De La Salle faced Kilkenny CBS in the All-Ireland final on 22 April 2007.
[2] On 8 March 2008, O'Keeffe won a second successive Harty Cup medal following a 1-11 to 0-07 defeat of Thurles CBS in the final.
[3] On 19 April 2008, he won a second successive All-Ireland medal following De La Salle's 2-09 to 2-08 defeat of Thurles CBS in a final replay.
On 1 March 2014, he lined out in goal when Waterford IT defeated the Cork Institute of Technology by 0-17 to 0-12 to win the Fitzgibbon Cup.
[5] O'Keeffe joined the Ballygunner club at a young age and played in all grades at juvenile and underage levels.
On 12 November 2006, he was just 15-years-old when he lined out in goal when Ballygunner defeated Cappoquin by 2-12 to 2-05 to win the Waterford Minor Championship title.
[8] O'Keeffe lined out in his second Waterford Senior Championship final on 24 October 2010, with Ballygunner hoping to retain the title for the first time in 12 years.
[9] Ballygunner qualified for a third successive Waterford Senior Championship final on 16 October 2011, with O'Keeffe lining out in goal once again.
[12] On 18 October 2015, O'Keeffe won a fourth Waterford Senior Championship medal following a 0-16 to 0-12 defeat of Tallow in the final.
[15] On 22 October 2017, O'Keeffe won a sixth Waterford Senior Championship medal in goal when Ballygunner defeated De La Salle by 2-18 to 0-16 in the final.
[19] On 13 October 2019, O'Keeffe was again in goal when Ballygunner faced De La Salle in the Waterford Senior Championship final.
[28] On 12 July 2015, he was also in goal when Waterford were beaten for the fourth time in six seasons by Tipperary in the Munster final.