In 1935 he led Real Betis to their first La Liga title, and during the Spanish Civil War he took Barcelona on a tour of North America.

He also played junior football with several local Dublin clubs, including Frankfort, Stranville Rovers and Liffey Wanderers, before joining Belfast Celtic.

[4] A terrific performer in the heart of the defence, O'Connell made his English First Division debut for Sheffield Wednesday against Bury on the last day of the 1908–09 season.

However, in subsequent seasons, he was unable to establish himself as a regular in the Wednesday first team, due to competition from English McConnell, Jimmy Spoors and Bob McSkimming.

[5] [6] O'Connell's time at United saw the club finish third from bottom in the First Division, narrowly avoiding relegation by a single point.

[3] In August 1919, O'Connell moved to Dumbarton; during the 1919–20 season, he made 31 league appearances and played twice in the Scottish Cup.

He made his Scottish League debut as a right-half in a 1–1 draw with Ayr United on 16 August 1919, the opening day of the season.

Their home ground was upgraded from a typical non-league venue containing no more than a simple seated and covered stand to a stadium designed for 20,000.

Ashington eventually finished the season in a respectable tenth position, with O'Connell making his last appearance for the club in a 2–2 home draw against Southport.

In 1914, together with Harris, Lacey, Louis Bookman and Billy Gillespie, he was a member of the Irish team that won the 1914 British Home Championship.

O'Connell then captained the team, while playing with a broken arm, as a ten-man Ireland clinched the title with a 1–1 draw against Scotland at Windsor Park on 14 March.

[16] O'Connell's success with Real Betis attracted the interest of Barcelona, who appointed him as successor to Franz Platko for the 1935–36 season.

In early 1937, Barcelona received an offer from a businessman, Manuel Mas Serrano, via one of their players, Josep Iborra.

Serrano proposed that the club travel to play a series of exhibition matches in Mexico and the United States.

[19][20] Due to the financial success of this tour, Barcelona cleared their debts and saved the club; however, O'Connell returned to Spain with only four players, after the others chose to go into exile in Mexico and France.

[15][23] A bust commemorating O'Connell's league title achievement with Real Betis was installed at the club's Estadio Benito Villamarín in 2017.