Shares (with Marlon Devonish) the record number of appearances by a GB athlete at the World champs with eight.

Has ran below 46 seconds for the 400m on 107 occasions.

Winner of six national titles - five senior and one u20.

Records ^{as of April 2020}
4x400mx NR ER - 3:12.27

U20 400m NR - 45.35

Major Championships and International Record
2019 - World Championships - 4x400m mx 4th.
2018 - European Championships - 400m 6sf3, 4x400 BRONZE.
2017 - World Championships - 400m 6h4, 4x400 BRONZE.
2016 - Olympic Games - 400m 5h4, 4x400 DQh. European Championships - 400m GOLD.
2015 - World Championships - 400m 6sf3, 4x400 BRONZE.
2014 - European Championships - 400m GOLD, 4x400 GOLD. Commonwealth Games - 400m 4th.
2013 – World Championships - 4x400m BRONZE
2012 – Olympic Games - 5th sf, 4x400m BRONZE
2011 – World Championships - 400m 7th sf, 4x400m 7th
2010 – European Championships - 400m BRONZE, 4x400m SILVER
2009 – World Championships - 400m 7th sf2, 4x400 SILVER
2008 – Olympic Games - 400m 6th, 4x400m 4th.
2007 – World Championships - 400m 4th ht, 4x400m 6th
2006 – Commonwealth Games - 400m 5th, 4x400m 4th. World Junior Championships - 400m BRONZE, 4x400m BRONZE
2005 – World Championships - 4x400m 4th. European Junior Championships - 400m SILVER, 4x400m GOLD

Domestic Championships Record
2019 - British Championships - 400m 8th.
2018 - British Championships - 400m 5th.
2017 - British Championships - 400m 5th.
2016 - British Championships - 400m Bronze.
2015 - British Championships - 400m Bronze.
2014 - British Championships - 400m Gold.
2012 – British Championships - 400m Gold.
2011 – British Championships - 400m Gold.
2010 – British Championships - 400m Gold.
2008 – British Championships - 400m Gold.
2007 – British Championships - 400m Silver.
2006 – British Championships - 400m silver.
2005 – England U20 Championships - 400m Gold.

Martyn Rooney initially trained and competed at the middle distance events of 800m and 1500m and also participated in cross country events throughout the winter months. His talent for the 400m was discovered by coincidence when he was asked to make up some points for his club at a London fixture. He made a great impact in 2005 when he won the national junior title, before winning a silver medal at the European Junior Championships, followed by a storming leg in the 4x400m relay at the World Championships in Helsinki.