Youth career Melia began playing football with local club Newtown Juniors, where he played until joining St Joseph's Boys at under-12 level. He later joined
Bray Wanderers for a short stint, before moving to
League of Ireland Premier Division side
St Patrick's Athletic in the summer of 2022.
St Patrick's Athletic 2023 season His performances for the youth team of St Patrick's Athletic earned him a call up to the senior squad in January 2023, and he made his debut in a
Leinster Senior Cup, coming off the bench to score in a 3–1 loss to
Wexford. In May 2023, with
Eoin Doyle suspended and
Tommy Lonergan ill, Melia was again drafted into the senior squad, and made his league debut as a substitute for
Conor Carty in an eventual 3–0 win against
Drogheda United in the LOI Premier Division. He became the club's youngest league debutant, and the third youngest in league history - behind
Sam Curtis &
Evan Ferguson. After the game, manager
Jon Daly lauded Melia as an "exceptional" player. Following his performances for St Patrick's Athletic, he was linked with a move to English
Premier League side
Liverpool in March 2023. On 30 June 2023, Melia came off the bench to score his first senior league goal in a 7–0 win over
UCD at
Richmond Park, with the goal making him the youngest ever goalscorer in the
League of Ireland Premier Division at 15 years and 281 days old. In August 2023, he spent time on trial at
Manchester City. On 20 August 2023, Melia scored the winning penalty in a 4–3 shootout win over
Derry City in the second round of the
FAI Cup after a 0–0 draw at the
Ryan McBride Brandywell Stadium. On 22 September 2023, on his 16th birthday, Melia came off the bench in the 83rd minute against
Dundalk, before going on to win a penalty in injury time which he took himself and scored to secure a 3–1 win. On 9 November 2023, it was announced that Melia had signed his first professional contract with the club, signing a 3-year contract to keep him with the club until the end of the 2026 season. On 12 November 2023, Melia came off the bench in the 57th minute of the
2023 FAI Cup Final, making him the youngest ever player to play in an
FAI Cup Final, as his side beat
Bohemians 3–1 at the
Aviva Stadium in front of a record breaking FAI Cup Final crowd of 43,881.
2024 season His first goal of the
2024 season came on 22 January in a
Leinster Senior Cup game away to Usher Celtic. Melia scored his first league goal of the season on 1 August 2024, coming off the bench in the 77th minute at home to
Sligo Rovers and finding the bottom corner 9 minutes later from 25 yards to help his side to a 3–0 victory. On 10 May 2024, Melia scored the final goal of the game in a Dublin derby away to
Shamrock Rovers in a 2–2 draw at
Tallaght Stadium. On 31 May 2024, Melia scored a backpost header to open the scoring in a 2–1 win over
Galway United to help his side to their first league win under new manager
Stephen Kenny. On 25 July 2024, Melia made his first European appearance of his career, starting up front in a 3–1 win over
Vaduz of
Liechtenstein in the
UEFA Conference League. On 1 September 2024, Melia replaced
Aidan Keena from the bench in the 76th minute at home to
Drogheda United and scored the final goal of the game by finding the bottom left corner from 25 yards in the 93rd minute of a 4–1 win. On 5 September 2024, he again scored after coming off the bench, this time heading home the winner in the 68th minute of a 2–1 win away to
Dundalk at
Oriel Park, just 6 minutes after coming off the bench. Melia was voted by supporters as the club's Young Player of the Year at the club's end of season awards night. On 23 November 2024, Melia was named
PFAI Young Player of the Year by his fellow professionals across the league, becoming the youngest winner in the award's 43 year history.
2025 season On 14 March 2025, Melia scored his first goal of the season, getting on the end of
Jason McClelland's ball across the 6 yard box for his sides second goal of the game in a 3–0 win over
Bohemians at
Richmond Park. On 18 April 2025, he opened the scoring in a 2–2 draw at home to
Shamrock Rovers with a back post volley on the turn that bounced through the legs of
Edward McGinty. He scored his third goal of the season on 9 May 2025, opening the scoring away to
Shelbourne in the 29th minute at
Tolka Park. On 16 May 2025, Melia opened the scoring in a 3–2 victory over
Cork City at
Richmond Park with a bullet header from a
Barry Baggley corner. On 23 May 2025, he scored a brace in a 2–2 draw at home to
Waterford for his 4th goal in 4 games. On 17 July 2025, he scored the first European goal of his career, when he opened the scoring in the 6th minute away to
Hegelmann of
Lithuania, before assisting
Kian Leavy's goal in the 56th minute of a 2–0 win for his side as they progressed to the next qualifying round of the
UEFA Conference League. On 3 August 2025, Melia opened the scoring in a 2–0 win away to
Waterford at the
RSC. On 10 August 2025, he scored his 9th and 10th goals of the season in a 3–0 win over
Sligo Rovers at
Richmond Park. On 17 August 2025, Melia opened the scoring in a 2–0 win at home to rivals
Shelbourne in the
FAI Cup. On 29 August 2025, Melia scored his 10th league goal of the season with a solo effort in the 40th minute away to
Derry City, before assisting
Chris Forrester for a second half goal. On 22 September 2025, he scored twice in a 4–0 win at home to
Cork City on his 18th birthday. On 24 October 2025, Melia scored in a 1–1 draw with
Waterford in his final home appearance for the club, putting him level as the league's top goalscorer with
Pádraig Amond on 13 goals. On 27 October 2025, he was voted by the club's supporters as St Patrick's Athletic Young Player of the Year for the second season in a row.
Tottenham Hotspur On 4 February 2025, it was announced that
St Patrick's Athletic had agreed the transfer of Melia to
Premier League club
Tottenham Hotspur on a contract until the summer of 2031, commencing in January 2026 for an undisclosed record transfer fee for a
League of Ireland player, reported to be €2 million up front, rising to €4 million with add ons, plus a 20% sell on clause. He officially joined up with Tottenham on 1 January 2026, with manager
Thomas Frank stating that he would assess Melia up close in training before making a decision on his immediate future with the club, with a loan move a possibility. On 4 April 2026, Melia made his debut for the
Tottenham Hotspur U21s in a 3–2 win over
West Ham United U21 and scored in the 70th minute, 3 minutes after replacing
James Wilson from the bench. ==Personal life==