Career
Due to having Northern Irish grandparents, English-born Magnay is eligible to represent Northern Ireland or the Republic of Ireland. He made his international debut the Northern Ireland U-21 team on Tuesday 11 August 2009, in an away friendly against Portugal"s U-21 team Prior to this Magnay was part of Leeds United"s academy.
On 30 July 2007, ChelseaTV Online conducted an interview with Magnay, where it was revealed he had signed professional forms with the club
In January 2009 he was loaned to League One team Milton Keynes Dons. He made his debut for the Dons on 31 January against Cheltenham Town.
He made only one other appearance and in total played 7 minutes for MK. On 9 March 2009 Magnay was signed by Northampton Town on a one-month loan deal. He made his debut in the 1–0 defeat at Millwall.
In pre-season ahead of the 2009-2010 Premier League campaign, Magnay was a part of the Chelsea Reserves team that took part in a training ground brawl with United Arab Emirates side First Rate (at Lloyd's)-Ahli.
In March 2010 Magnay suffered a serious injury in a reserve team game against Charlton Athletic, damaging his anterior cruciate ligament, medial collateral ligament and cracking his kneecap. On 16 June 2011, it was announced that Magnay had been released by Chelsea having made no senior appearances in a spell plagued by injury. Also, Chelsea reserve team coach Steve Holland made this comment in an article which confirmed the departure of two other players: "Carl Magnay will remain at Chelsea for the rest of this year and he is well informed of how the club see him.
He is another who had an awful run of injuries and we try to look after our players.
Hopefully over the next six months we can help place him at a good level of football."
Gateshead
In January 2012, Magnay appeared on trial at Gateshead, playing for Gateshead"s reserve side in a Durham Challenge Cup match against Norton & Stockton Ancients on 11 January and a Central League game against Hartlepool United Reserves on 25 January. On 27 January 2012, he signed for Gateshead on a contract until the end of the season.
He agreed a new one-year contract with the club in May 2012 to cover the 2012-2013 season. Magnay scored his first career goal on 29 January 2013 against Barrow in the FA Trophy.
He scored his first league goal on 13 April 2013 against Hereford United.
After making 77 appearances for the club, Magnay was released at the end of the 2013-2014 season. Grimsby Town
On 15 July 2014 Magnay signed for Conference Premier side Grimsby Town on a one-year contract. Hartlepool United
On 1 June 2015, Magnay joined Hartlepool United after a successful spell at Grimsby where he helped his team finish 3rd in the Conference Premier.