Background
Siejka was born in Bathurst in regional New South Wales and played his junior rugby league for the Bathurst Panthers.
Siejka was born in Bathurst in regional New South Wales and played his junior rugby league for the Bathurst Panthers.
He has also played for National Rugby League club Street George Illawarra Dragons and Wakefield Wildcats in the Super League. His preferred position is at five-eighth but he can also play halfback. Siejka joined the Penrith Panthers in 2008 on a A$ 75,000 three year deal, a then record for a 16-year-old.
He played for the Australian Schoolboys under-15 side.
On 30 July 2011, Siejka made his National Rugby League debut for the Panthers against the North Queensland Cowboys. Siejka made 25 tackles and kicked a goal in his side"s 30-18 loss at Dairy Farmers Stadium.
In his second first grade appearance for the Panthers, Siejka set up two of Penrith"s three tries thanks to a grubber kick leading to Trent Waterhouse"s 39th NRL career try, and then in the dying stages in the game he played a vital role into Ryan Walker"s try via some "hot potato football" from Junior Vaivai. Siejka joined the New Zealand Warriors for the 2013 season.
On 12 June 2013 Siejka was released from his Warriors contract, after failing to make a single first-grade appearance for the club
He subsequently joined the Saint George Illawarra Dragons for the remainder of the 2013 season and began training with their NSW Cup team, the Illawarra Cutters. 2015 - 2015 Season
Siejka signed for Bradford on a 2 Year Deal. He featured in the pre-season friendlies against Castleford Tigers and Leeds Rhinos.
He scored against Castleford Tigers (1 goal).
He featured in Round 1 (Leigh Centurions) to Round 2 (Whitehaven RLFC). Harry was banned for two rounds before playing in Round 5 (Batley Bulldogs) to Round 9 (London Broncos).
He played in Round 18 (Workington Town) then in Round 13 (Featherstone Rovers). Siejka played in Qualifier 2 (Wakefield Wildcats) then in Qualifier 5 (Hull KR) to Qualifier 7 (Halifax RLFC).
Harry played in the £1 Million Game (Wakefield Wildcats).
He also featured in the Challenge Cup in Round 4 (Workington Town). He scored against Leigh Centurions (2 goals), Whitehaven RLFC (2 goals) and Workington Town (1 try). He was released from his contract by mutual consent on 6th November 2015.