[6] He progressed from the under-18 team through to the under-23s during 2018, enjoying impressive scoring form, including a brace in a 2–1 win over Dagenham & Redbridge in the FA Youth Cup on 16 January 2018.
[8] He made his professional debut for the club on 21 October 2018, coming on as a substitute in a 2–0 home defeat to Queens Park Rangers.
[13] His impressive progress and lone goal earned him the club's Young Player of the Year award for the 2018–19 season.
[14] He recovered and returned to the first team for pre-season, but suffered another stress fracture injury to his back in a friendly against Fortuna Düsseldorf in July.
[19] On 25 June 2021, Lankester joined fellow East Anglia club Cambridge United for an undisclosed fee, ending his 15-year association with Ipswich Town.