As manager of Wales, Speed is often credited as being the catalyst for the change in fortunes of the national team and as setting the pathway to future successes.

[12] Whilst at school, he was employed as a paperboy and played for Flintshire Schoolboys, a local boys' team, and for Aston Park Rangers.

[1] Leeds manager Howard Wilkinson first noticed Speed in a youth team game while the player was playing in a left back position.

[15] Under Wilkinson, he made his first team debut aged 19 in a goalless draw against Oldham Athletic in the Football League Second Division.

[15] He went on to play a key role, playing 41 of a possible 42 games and scoring seven goals,[17] as Leeds won the Football League First Division championship title in 1992,[18] as part of a midfield that also comprised Gordon Strachan, Gary McAllister and David Batty – former Leeds manager Eddie Gray considered it to be one of the greatest midfield line-ups in the modern era.

He told the Liverpool Echo: "You know why I'm leaving, but I can't explain myself publicly because it would damage the good name of Everton Football Club and I'm not prepared to do that.

[36] He also played in the UEFA Champions League with Newcastle in the 2002–03 season, scoring the 58th-minute equaliser in a 2–1 home victory over Dynamo Kyiv in the group stage on 29 October 2002.

Having seen his penalty parried, Speed netted the rebound to score his first goal for United in a victory over Coventry City in March of that year.

[45] In an interview with BBC Wales on 10 May 2008, Speed hinted that the 2008–09 season may be his last playing before moving into coaching or management but stated that he had not yet made up his mind.

[47] Despite undergoing surgery to correct the problem he failed to regain his fitness and missed the rest of the season, concentrating instead on a coaching role at the club.

[49] He continued training and completed the 2010 London Marathon in aid of the Sir Bobby Robson Foundation, the cancer charity founded by Speed's former Newcastle manager, who had died of the illness in 2009.

[1] He played 85 times for Wales, making him the second highest capped player only behind goalkeeper Neville Southall who made 92 appearances[53] until Speed was surpassed by Chris Gunter in 2018.

His first appearance for the national side had come on 20 May 1990 in a 1–0 friendly win against Costa Rica at Ninian Park as a second-half replacement for Glyn Hodges.

[55] Speed broke the record held by Dean Saunders for most caps by a Welsh outfield player when he won his 76th against Finland in a Euro 2004 qualifier on 10 September 2003.

[57] Hardworking, honest and self-critical,[13] he was not blessed with exceptional talent at a young age, but instead developed his technique through many hours of hard work on the training field.

[59] He also had a reputation as a friendly and supportive person, who cared for and took an interest in the lives of the people around him;[60] his 'nice guy' persona made him a popular and well respected figure amongst his peers.

[62] On 11 December 2010, Speed was linked with the vacant Wales manager job along with John Hartson, Brian Flynn, Chris Coleman and Lars Lagerbäck.

[64] With just four months managerial experience, Speed was confirmed as the new Welsh national team manager on 14 December 2010 succeeding John Toshack who had stepped down in September 2010.

[79] In 2018, seven years after his death, an old letter written by Speed in which he noted being depressed and wishing to sleep and "never wake up" was uncovered by his widow Louise.

[80] On 26 November 2011, Speed appeared as a guest on the BBC One television programme Football Focus;[81] presenter Dan Walker later described him as being in "fine form".

[85] The coroner at the inquest reached a narrative verdict, but that there was insufficient evidence to determine whether it was intentional as he may have intended to make a "dramatic gesture" and then "nodded off to sleep".

Close friends and former teammates such as Robbie Savage, Ryan Giggs, Simon Grayson, Alan Shearer, Craig Bellamy and John Hartson all expressed their deep sorrow at his death.

[91][92][93][94] Many British politicians expressed sadness at Speed's death and sent condolences to his family, including Prime Minister David Cameron and Leader of the Opposition Ed Miliband.

[97] The match between Swansea City and Aston Villa at the Liberty Stadium, held only hours after Speed's death was announced, was dedicated to his memory.

Collins' Villa teammates Shay Given and Jermaine Jenas had both played with Speed at Newcastle United, and both were badly affected by the news.

Speed's fellow midfielders from the 1991–92 title-winning side Gary McAllister, David Batty and Gordon Strachan laid wreaths in his memory.

[106] On 4 January, the Football Association of Wales announced that a match in Speed's memory would be played on 29 February at Cardiff City Stadium.

In keeping with his wife Louise's wishes, only small crowds gathered on the main road outside St Deiniol's Church and no members of the press were admitted.

[110] Speed's work to improve the professional standard of the Football Association of Wales, including improvements to training facilities, team culture, and its national visibility, was credited as a major contributor to the success that Wales would enjoy in the decade after his death, beginning with their qualification for Euro 2016 and culminating in their appearance at the 2022 FIFA World Cup in Qatar, bringing to an end a 64-year drought at the World Cup.

"[113] Wales captain Gareth Bale paid tribute to Speed on the occasion, saying "Gary Speed's vision was to grow the FAW, not just the football, but the infrastructure: building a training base, having a high-performance centre and recovery centre, just like a top club," adding "I'm sure he's looking down on us with a big smile and happy that Welsh football is in a great place.