The 20-year-old, who joined Liverpool from Sunderland in 2019, made his senior debut under Jurgen Klopp in 2023, coming off the bench against Toulouse in the Champions League.
He has since made 13 appearances and captained the Reds' U21 side.
McConnell’s old contract was set to expire next summer, but he has agreed to fresh terms with Liverpool until 2029, The Athletic reported on Tuesday.
Liverpool are believed to view the controlling midfielder as a future first-team regular.
He will now continue his development in the Eredivisie, where Ajax, managed by former Liverpool assistant Johnny Heitinga, have secured his signature.
The Dutch giants are understood to have beaten interest from West Brom, Hull, Oxford United, Sturm Graz, and several other European clubs in the race to sign McConnell.
Swift negotiations, Champions League football, and Heitinga's first-hand familiarity with Arne Slot’s game are thought to have given Ajax the upper hand.
The club have been seeking a new midfielder since the departure of former captain Jordan Henderson, who left on a free transfer in June before returning to the Premier League with Brentford.