Born in Salford, Lancashire, Kiely trained with the West Bromwich Albion youth system as a schoolboy before being accepted into the FA School of Excellence at Lilleshall.

Bury requiring a point to guarantee a second automatic promotion in as many seasons had Kiely to thank after he kept the scoreline at 0–0 in a memorable day at Vicarage Road.

[9] He then joined Championship side West Bromwich Albion on 30 January 2007, signing a one-and-a-half-year contract, as a replacement for Russell Hoult.

[11] Kiely reached the milestone of 700 senior career appearances on 1 September 2007, and recorded a clean sheet as Albion beat Barnsley 2–0.

[15] He nonetheless kept 18 clean sheets in all competitions to win the Championship Golden Glove award, while Albion won promotion to the Premier League as champions and reached the FA Cup semi-final.

[17] And following an injury to Carson in training, Kiely was handed his first Premier League start against Wigan Athletic on 9 May 2009, producing some fine saves as the Baggies won 3–1 to keep their survival hopes alive, earning praise from Mowbray in the process.

Since relegation to the Championship Kiely has once again had to be content playing second fiddle to Carson, who was named the new club captain by new manager Roberto Di Matteo, but on 8 December 2009 he made his first Championship appearance of the season as a replacement, coming on for the sent-off Carson and saving a penalty (though Peter Whittingham scored from the rebound) in a 2–0 home defeat to Cardiff City.

[1][28] He went on to represent the Republic of Ireland at full international level, earning his first cap as a substitute in a UEFA Euro 2000 qualifying play-off against Turkey in November 1999.

[29] He retired from international football in February 2003,[30] but in April 2008 Ireland's assistant manager Liam Brady suggested that Kiely could make a return to the squad.

[33] On 28 May 2009, he walked out of the Ireland squad after Trapattoni informed him that he would be replacing Shay Given with Keiren Westwood for the second half of the friendly International against Nigeria at Craven Cottage on 29 May.

[35] Away from football, Kiely made a guest appearance on Bravo's Saved by the Ball lifestyle makeover programme in 2006, and has also worked as a match summariser for BBC Radio 5 Live.