The right-back came on as a second-half substitute as Roberto De Zerbi’s side drew 1-1 with the Magpies at St. James Park.
Joel Veltman has given Brighton a 1-0 lead in the 18th minute but the Seagulls squandered their advantage late in the first half as Sean Longstaff restored parity for Newcastle.
Lamptey replaced goal scorer Veltman in the first half after the Dutch full-back suffered an injury and was unable to continue.
Having marked his 100thappearance in a Brighton shirt, the 23-year-old took to social media to revel in the moment.
"Tough point away from home. 100 games for Brighton and Hive Albion. Swipe to see the first. Thank you all for the support. Get back safe," he wrote on Twitter.
Lamptey came through the Chelsea academy but left the Blues to join Brighton in 2020 due to a lack of first-team opportunities.
The right-back has been part of the Seagulls’ most successful era, having qualified for the UEFA Europa League and reached the FA Cup semi-final last season.
Although he has been blighted by injuries this season, Lamptey has still managed 23 appearances in all competitions and has four assists to his name.
The former Chelsea defender missed Ghana’s campaign at the 2023 Africa Cup of Nations (AFCON) due to injury but is in line for a recall for next month’s 2026 FIFA World Cup qualifiers against Mali and the Central African Republic (CAR).