In a career playing in all top four English leagues he started at local side, Rochdale, then going on to play for Watford, Brighton & Hove Albion and Sunderland, and had brief loan spells with Leeds United, Birmingham City and Sheffield Wednesday, finishing his career with Bolton Wanderers after a three-year spell.

[5] Having played in the club's reserve side, he went on to make his first league appearance in Rochdale's 4–2 home defeat against Hereford United on 12 February 2008.

[14] After being sidelined for two matches, Buckley scored on his return to the first team from absent, as well as, assisting one of the goals, in a 3–1 win over Accrington Stanley on 3 January 2009.

[17][18] Then in September 2009, Buckley scored three goals in a spell of three consecutive games against Northampton Town, Hereford United and Darlington.

[19][20][21] Despite suffering from injuries, Buckley made 18 appearances for Rochdale in 2009–10, scoring 3 goals in a spell of 3 consecutive games in September 2009.

[26] On signing, Watford manager Malky Mackay said of Buckley: Will's an exciting young talent who has impacted upon Rochdale ...

[33] After scoring a hat-trick against Boreham Wood in the pre-season friendly, Manager Malky Mackay hope the partnership of Buckley and Danny Graham for their performance.

[49][50][51] It wasn't until 3 December 2011, that Buckley again came off the bench to score an injury-time winner – a 92nd-minute goal in a 1–0 victory over Nottingham Forest.

[54] Against Newcastle United in the FA Cup fifth round, Buckley's shot was deflected to cause the own-goal that gave Brighton a shock 1–0 win.

[55] His performance throughout saw him being nominated for January's Player of the Month, but lost out to Birmingham City's defender Curtis Davies.

In the 2013–14 season, Buckley continued to be in the first team regular at the club and played as an orthodox wide man under the new management of Óscar García.

[86] On 14 August 2014, Buckley transferred to Premier League club Sunderland for an undisclosed fee, reported as £2.5 million, signing a three-year contract.

[89] Buckley made his Sunderland debut, in the opening game of the season, where he came on as a second-half substitute, in a 2–2 draw against West Bromwich Albion.

[90] In the next match against Manchester United, Buckley made his first start and played well, in a 1–1 draw, with the Daily Mirror describing his performance as "provided a consistent attacking threat down the right".

[92] Buckley then played a vital role in two separate matches against Crystal Palace and rivals' Newcastle United when he provided two assists to give them a rare wins on 3 November 2014 and 21 December 2014 respectively.

[95] Although he returned to the first team on the bench for the rest of the season, he once played in the reserve side and scored, as well as, assisting one of the goals, in a 3–2 win over Southampton Under-21 on 5 April 2015.

[102] After making four appearances, Buckley's first team was restricted to substitute bench and remained there until he was recalled by his parent club in late-November.

[103][104] Despite being linked a move abroad to AEK Athens, where Poyet was based,[105] it was confirmed on 15 January 2016, Buckley joined Championship club Birmingham City on loan for a month.

[106] He made his first appearance the following day, as a very late substitute with Birmingham already 3–0 up away at Derby County,[107] but played a rather greater part in his home debut, against Ipswich Town a week later.

Brought into the starting eleven after Jacques Maghoma withdrew through illness, he produced an energetic performance, found himself in the right place to score the opening goal after several attempts had been blocked, and was the victim of a foul for which Jonathan Douglas was sent off just before half-time; Birmingham won 3–0.

[112] Four days later, on 9 August 2016, Buckley made his Sheffield Wednesday debut in the first round of EFL Cup against Cambridge United, where he played 120 minutes, as they lost 2–1.

[124][125] Buckley is eligible to play for the Republic of Ireland through his grandfather and in 2013, encouraged by his then Brighton teammate Stephen Ward, expressed his desire to declare.