Born in Santos, São Paulo, Lucas Lourenço joined Santos' football youth categories in 2013, after playing for the club's futsal team. On 2 October 2017, he signed his first professional contract with the club, lasting until September 2022.[1]
In January 2018, Lucas Lourenço was promoted to the main squad by new manager Jair Ventura,[2] but was demoted back to the under-17s in the following month.[3] He subsequently moved to the under-20 squad before returning to the first team under new manager Cuca.
Lucas Lourenço made his first team – and Série A – debut on 2 December 2018, coming on as a second-half substitute for Jean Mota in a 2–1 away loss against Sport.[4] On 1 September 2020, despite only featuring for the under-20s, he renewed his contract until December 2024.[5]
On 15 September 2020, Lucas Lourenço made his Copa Libertadores debut by replacing fellow youth graduate Alison in a 0–0 home draw against Club Olimpia.[6] On 20 July of the following year, he moved to Série B side Londrina on loan until the end of the season.[7]
In September 2021, after missing trainings, Lucas Lourenço's loan was cut short and he returned to Santos.[8] On 14 December, he was loaned to Santo André for the 2022 Campeonato Paulista.[9]
On 6 July 2022, Lucas Lourenço was loaned to CSA for the remainder of the 2022 Série B.[10] On 18 November, he moved to fellow league team Botafogo-SP also in a temporary deal.[11]
On 4 July 2023, Lucas Lourenço moved to Série C side Figueirense on loan for the remainder of the year.[12] On 1 February 2024, he rescinded his contract with Santos.[13]