Blake received criticism from a number of former managers, including Dave Jones, Malky Mackay and Chris Coleman, during his career regarding his fitness levels.

[7] Blake made his professional debut on 17 April 2006 against Crewe Alexandra in the Football League Championship, following injuries to several first team players,[8] replacing Jeff Whitley as a late substitute during a 1–1 draw.

[15] At the start of the 2008–09 season, Blake was placed on a special training regime by the club to correct his posture in an attempt to remedy long-term injury problems after being substituted in the opening 20 minutes of a League Cup tie against Milton Keynes Dons.

[16] On 28 August 2009, Blake signed for fellow Championship club Plymouth Argyle on loan until January 2010,[17] making his debut the following day in a 3–1 defeat to Sheffield Wednesday.

[24][25] Blake missed Cardiff's 2011–12 pre-season schedule through injury but returned in a 1–1 draw with Burnley on 20 August 2011, coming on as a substitute in place of Joe Mason.

[29] The newly formed partnership of Mark Hudson and Ben Turner were preferred ahead of Blake, who later confirmed his desire to hold talks with boss Mackay over his future at Cardiff having not featured for the club in over a month.

[30] At the end of the season, he played in the 2012 Football League Cup Final, replacing McNaughton in extra time as Cardiff went on to lose to Liverpool in a penalty shootout.

[33] With his contract due to expire at the end of the season, Mackay accepted an offer of £350,000 from Crystal Palace in order to avoid Blake leaving on a free transfer the following summer,[5] with the deal being completed on 24 August 2012.

Wales manager Chris Coleman publicly criticised Blake's fitness levels after revealing that he had been deemed too unfit for Palace's reserve side and stated "Darcy has got to be fitter.

[3] His signing was branded a "transfer coup" by County manager Justin Edinburgh and he made his debut for Newport in a League Two match against Torquay United on 22 March.

Usually playing at right back, he was part of the team that finished top of their qualifying group for the 2009 UEFA European Under-21 Football Championship before losing in the playoff match against England.

[45] Blake made his full international debut on 12 October 2010, being named in the starting line-up for a 4–1 defeat to Switzerland in Basel before being replaced by Christian Ribeiro after 54 minutes.

On 10 August 2011, Blake scored his first senior career goal in a 2–1 defeat against Australia and was named in the starting line-up in the side's following match against Montenegro due to James Collins being suspended.