|Date of birth||25 March 1980|
|Place of birth||Sligo, Ireland|
|Height||1.85 m (6 ft 1 in)|
|2007||→ Fredrikstad (loan)||6||(0)|
|* Senior club appearances and goals counted for the domestic league only.
Martyn played with Derry City from 2002 until his loan move to Fredrikstad F.K. in 2007. He is one of the few players (if not the only one) who have paid to play for Derry City. Having signed a pre-contract with Shelbourne a number of seasons ago, he changed his mind and was forced to pay £8,000 to escape the agreement. An attacking midfielder with an eye for goal, the Sligo man moved to Derry to show his commitment to the club.
In August 2006 Martyn scored twice in the 2006–07 UEFA Cup win over Gretna F.C. . In November 2006 he made his 200th appearance for the club when he was brought on as a 60th-minute substitute against Cork City FC in the Brandywell. This made him the 16th player to reach this mile-stone since Derry's inception to the League of Ireland in 1985. He finished the 2006 season as Derry's second-highest scorer with 15 goals scored in total. This tally included 8 goals scored in the Premier Division and another 7 scored in the cup competitions.
Following financial difficulties at the Brandywell, it was announced on 19 January 2010 that Martyn had left Derry City and signed for Glentoran.
Ciarán Martyn suffered a tricky first year and a half at Glentoran due to long term injuries however when he was fit to play he was approaved very well by the supporters of Glentoran, Martyn scored on his Glentoran debut against Coleraine however the Glens managed to get beat 4–3 at the Coleraine Showgrounds.
Ciarán Martyn a player known for goal scoring, a massive midfielder and highly rated.
Ciarán Martyn took a four figure pay cut for Glentoran under manager Scott Young. It was first announced in an edition of the Glentoran Gazette match day magazine.
Ciarán Martyn was issued the number six jersey at Glentoran for the 2011/12 season.
Ciarán is a first cousin of British 400m runner Martyn Rooney.
Ciarán was released from Glentoran on 24/5/12.
He then joined Glenavon on a short-term contract in November 2012 before signing a one and a half-year deal with the club on 8 December.
Martyn featured when Glenavon beat Ballymena United 2–1 in the 2014 Irish Cup final, he also played in the 2016 final, in which Glenavon defeated Linfield 2–0.
- FAI Super Cup (1): 2000–01
|UCD Supporters' Player of the Year