Duggan joined the Clooney-Quin club at a young age and played in all grades at juvenile and underage levels before eventually progressing onto the club's senior team. On 15 October 2017, Duggan was named at left wing-forward but played at full-forward when Clooney-Quin qualified for their first Clare Senior Championship final in 73 years. He scored ten points, including a last minute free to secure a 1-16 to 0-19 draw with Sixmilebridge. Duggan top scored again with ten points in the replay, however, Clooney-Quin were defeated by 1-20 to 1-14. Duggan was called up to the Clare senior hurling team by Davy Fitzgerald in 2012. He made his first appearance on 7 February in a 2-13 to 1-13 defeat of Limerick in the pre-season Waterford Crystal Cup. Duggan was an unused substitute for the subsequent National Hurling League and All-Ireland Championship campaigns. On 10 February 2013, Duggan claimed his first silverware when Clare defeated Tipperary by 1-21 to 1-13 to win the Waterford Crystal Cup. He made his first National League appearance on 14 April in a 0-31 to 2-23 defeat of Cork. On 2 June, Duggan made his first Munster Championship appearance when he came on as a 29th-minute substitute for Seadna Morey in a 2-20 to 1-15 defeat of Waterford. On 8 September, he was an unused substitute in the 0-25 to 3-16 draw with Cork in the All-Ireland final. Duggan was again an unused substitute for the replay on 28 September. In spite of remaining on the bench he won an All-Ireland medal after a 5-16 to 3-16 victory. On 23 January 2016, Duggan scored three points when Clare defeated Limerick by 0-18 to 0-17 to win the inaugural Munster League. On 1 May, he scored a point from right wing-forward in Clare's 0-22 apiece draw with Waterford in the National League final. Duggan was dropped for the replay on 8 May, however, he won a National League medal as a non-playing substitute following Clare's 1-23 to 2-19 defeat of Waterford. On 9 July 2017, Duggan lined out in his first Munster Championship final. After starting the game on the bench he was introduced as a 65th-minute substitute for Cathal Malone in the 1-25 to 1-20 defeat by Cork. On 1 July 2018, Duggan top scored with 1-07 for Clare in their 2-24 to 3-19 defeat by Cork in the Munster Championship final. On 8 August, he was voted as the PwC GAA/GPA Player of the Month for July as a result of his "outstanding form throughout this championship". Duggan, who ended the championship as top scorer with 3-76, was later named in the right wing-forward position on the All-Star team. On 21 July 2024, he started in the half-back line as Clare won the All-Ireland for the first time in 11 years after an extra-time win against Cork by 3-29 to 1-34, claiming their fifth All-Ireland title.