Early years Hardy began his playing career at his hometown club
Bedlington United before moving to Scotland with
Heart of Midlothian in 1910. He made his debut for the club on 2 April in a 2–2 draw with
Third Lanark at the age of 18, and made a further three league appearances near the end of the
1910–11 season. The following season, he made his first appearance in a 3–2 defeat against
Leith Athletic in the first round of the
East of Scotland Shield in September 1910. However, he made only one further appearance for the club, in a 3–0 loss to
St. Mirren two months later. He joined
Stockport County in early 1911 on a free transfer after being spotted by
Fred Stewart playing for Hearts' reserve team. Stockport had recently sold two players to the Scottish side with the deal including Stockport having the choice of any two from the club's reserves in return. Stewart travelled to watch them play and selected Hardy along with one other. Hearts initially denied the request as they did not wish to sell Hardy, but relented when Stewart reiterated the terms of the deal. Although they eventually sanctioned the move, Hearts stipulated that Stockport would be required to pay £200 if Hardy signed on for the following season. He made one senior appearance for the side, in a 4–0 defeat to
Leeds City in the
Football League Second Division on 1 April, but Stockport were unable to meet the £200 asking price to keep Hardy on for the
1911–12 season. His first signing in his new role was to bring Hardy to the club from Hearts who had retained his registration. The two sides agreed a fee of £25. although he was later reimbursed when finances improved. Cardiff achieved a higher finish in the
1912–13 season, winning the Second Division of the Southern League and gaining promotion to the First. Hardy missed only one league match during the campaign and scored his first senior goal for the club in a 1–1 draw with Pontypridd on 24 March 1913. The success was built around Hardy and Stewart's new signings,
Patrick Cassidy and
Kidder Harvey, who formed a partnership with Hardy that became known by fans as the "holy three". The side conceded only 15 goals en route to the Second Division title, and suffered a single defeat. The following year, Hardy recorded his first ever present season for the club; he played in all 38 matches as Cardiff finished 10th in the First Division and helped the side to their second Welsh Cup title in the penultimate season before the outbreak of World War I. During the war, Hardy served on the front lines and was wounded in action.
Southern League return and Football League When competitive football resumed after the war, Hardy immediately returned to Cardiff and remained a prominent first team player. He missed only one match during the
1919–20 season, featuring in 38 matches in all competitions. Cardiff joined the
Football League in 1920 and were placed in the Second Division. Hardy featured in the club's first match in the new league against his former side Stockport. In his tenth year since joining Cardiff, Hardy was awarded a
benefit match for a league fixture on 21 April 1921 against
Rotherham County, sharing the proceeds of the match with goalkeeper
Herbert Kneeshaw. Hardy was ever present for the second time in his career having played in all 42 league matches as he helped the side finish as runners-up and win promotion to the
First Division. He also scored his first goal in the Football League in a 1–0 victory over
South Shields on 16 April 1921. He eventually returned to the first team on 26 November, defeating
Everton 1–0. Two months into the following season, Hardy was approached to stand as a candidate for the
Labour Party in an election for
Cardiff City Council. Former Cardiff player
Charlie Brittain had successfully ran in previous years and was already serving on the council. He again made more than 35 appearances during the campaign and, in the
1923–24 season, he missed only two matches as Cardiff finished second in the First Division. In the
1924–25 campaign, Hardy played in all eight matches of the club's
FA Cup run as they reached the
final before losing 1–0 to
Sheffield United. He made a career high 52 appearances during the campaign, including all seven matches of the club's successful FA Cup run. He also helped the club to victory in the Welsh Cup, defeating
Rhyl in the final,
Later years After one further season, Hardy's advancing years saw his first team place come under threat. Cardiff were relegated from the First Division in the
1928–29 season, during which Hardy made 22 appearances in the league, his lowest tally in more than a decade. Cardiff suffered a second relegation the following year, to the
Third Division South. Hardy's long career with Cardiff established him as a revered figure among the club's support. Ahead of Cardiff's 1927 FA Cup victory, the
Daily Herald remarked "there is no more popular player in South Wales than "Billy" Hardy". It was said that when he appeared on a newsreel shown in Cardiff cinemas, the audience cheered for 10 minutes. Hardy remains Cardiff City's record appearance holder with 590 appearances over all competitions between 1911 and 1932. With the club suffering financially from the drop in divisions, Hardy was released by Cardiff in 1932. Shortly before the outbreak of World War II, Hardy was awarded a second benefit match by Cardiff, this time in a specially arranged match against
Fulham in May 1939.
Bradford Park Avenue Hardy retired from playing upon his release and left Cardiff after 21 years to take up a coaching position with Second Division side
Bradford Park Avenue. When the club directors chose not to extend the contract of manager Claude Ingram in 1934, Hardy was appointed in the role instead. He stepped down as manager at the end of the
1935–36 season having finished 15th and 16th in his two years in charge. He was replaced by
David Steele with Hardy instead returning to his coaching role at the club while also undertaking scouting assignments. ==Style of play==