Officials confirmed for Blackpool's League One play-off final against Lincoln City
and live on Freeview channel 276
Harrington, from Cleveland, has been refereeing in the Championship this season.
The official has handed out five red cards and 95 yellows in the 35 games he's taken charge of this term.
He officiated Lincoln City's League Cup game against Liverpool at the start of the season, which the Imps lost 7-2.
The last time he took charge of a game involving the Seasiders was in 2018, when he officiated Pool's home against Charlton Athletic.
Curtis Tilt was booked as the Seasiders ran out 2-1 winners thanks to goals from Armand Gnanduillet and Nathan Delfouneso.
Ian Cooper and Wade Smith will be the linesman at Wembley on Sunday, while Australian official Jarred Gillett will be the fourth official.
Goalline technology is in operation, but there is no VAR.
Chris Kavanagh will take charge of the Championship play-off final between Brentford and Swansea City, while the League Two final between Morecambe and Newport County will be officiated by Bobby Madley.
Madley took charge of the first leg of Blackpool's play-off semi-final against Oxford United, which they won 3-0 at the Kassam Stadium.
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