Lawlor was added to the Kilkenny senior team as a member of the extended panel for the 2018 Leinster Championship. He made his first appearance for the team on 10 November 2018 when he lined out at full-back in Kilkenny's defeat by Galway in the Wild Geese Trophy. On 27 January 2019, Lawlor made his competitive debut when he lined out at full-back in Kilkenny's 2–18 defeat of Cork in the National League. He made his first championship appearance on 11 May 2019 when he was at centre-back in Kilkenny's 2–23 to 1–21 defeat of Dublin. On 30 June 2019, Lawlor lined out at full-back when Kilkenny suffered a 1–23 to 0–23 defeat by Wexford in the Leinster final.[11] He was again selected at full-back when Kilkenny suffered a 3–25 to 0–20 defeat by Tipperary in the 2019 All-Ireland final. Lawlor ended the season by being nominated for an All-Star. On 14 November 2020, Lawlor won a Leinster Championship medal after lining out at full-back in the 2–20 to 0–24 defeat of Galway in the Leinster final