The season saw a new expansion club in Gateshead Thunder and a new rule abolishing transfer fees for all players over 24. Also, the season saw the first use of the 40/20 rule and the return of the non-scoring team restarting with a kick-off. 1999 was to prove to be Castleford's most promising for a few years.

Off the field, two new directors – Robert Elstone and Roger Hulley, joined the board. Jack Fulton took over as chairman.

Things started with 1 of the pre-season friendlies introducing Gateshead to its first ever game – and an 18–8 defeat. The Challenge Cup again launched the season and by the 6th game in Castleford were playing a semi-final against London Broncos. Here was another game to go down in the club's history for all the wrong reasons. The anguish felt by the town and all its supporters from a 27–33 defeat remained for many a year. The neutrals delight at an exciting game where the lead changed hands 4 times in the last 10 minutes was scant consolation to a devastated team’s dream of a Wembley appearance. To fight back to level in the final minute and still lose was indeed the stuff of nightmares. And the face in the nightmare will always be Steele Retchless – the scorer of London's winning try. Would Castleford have performed better than London in the final, who went down to a record 52–16 defeat to Leeds? – no-one will ever know.

The league programme had been revamped for this year to fit in more games as clubs felt they needed more income. As well as playing everyone home and away, each club would play 4 clubs in 1 extra game, the teams being decided on last season's league table.

There was no respite from the cup in the league for Castleford as the week after the semi final the Easter fixtures started, with Castleford's previous league form showing 1 scratchy 12-10 win over newly promoted Wakefield and 1 defeat. However, the spirit in the team and club came through and despite the cup disappointment Castleford lost only 1 of the next 8 games, 14–17 at home to Gateshead in a televised match that led coach Stuart Raper to claim that the 2 tries disallowed by the video referee would probably have been allowed in another game not on TV and would have changed the result.

Controversy continued in the away game at Wakefield a few weeks later after a 10–11 defeat. Castleford played the ball as the final hooter went and the referee disallowed a Brad Davis drop goal claiming it came after the hooter. Stuart Raper again let his feelings be known and was required to journey to the RFL headquarters to explain himself. They would not have known they would continue to hear from him, as he was about to sign a contract extension for a further 2 years.

During the year, Castleford set a new home Super League attendance record against Bradford of 10,122 and within a few weeks bettered it when 10,462 turned up for the Leeds game. These were Castleford's first five-figure Super League attendances. Interestingly, both games ended in draws, 18-18 with Bradford and 12–12 with Leeds.

By the season end Castleford had a record P30 W19 D3 L8 to finish 5th from 14 and join the top 5 Play-Offs. A total of 37 games were played and 24 players used. Francis Maloney registered 2 hat tricks in the season, others coming from Darren Rogers and Michael Eagar.

The first Play Off game was a trip to Wigan, to play the first ever match at the JJB stadium. Wigan's party was spoiled though as Castleford beat the reigning champions, for the third time in the season, by 14–10 in a strong defensive display. The prize was a trip to third placed Leeds 5 days later. Castleford were on a roll now and were not to be denied. Dale Fritz's first ever try for Castleford late on sealed a 23–16 win and a final eliminator tie at St Helens. Unfortunately that proved to be a game too far and a 6–36 defeat was scant reward for the effort. A recurring memory for all Castleford supporters present was the chanting of "barmy army" which took up when the game was getting beyond winning and did not end until the final hooter, seeming to last for over half an hour. The St Helen's supporters were amazed by this reaction and full of admiration for the continued support of the beaten team.

Off the field, the club did finish on a high, as captain Adrian Vowles was named Man of Steel and the club was awarded the title "Club of the Year" at the end of season awards ceremony.

After a season in 1998 without any reserve team beyond the Academy, an under 21 Alliance team was introduced to complement the under 18 Academy, which changed from under 19. Allan Agar was appointed to coach the Academy and Graham Steadman stepped up to coach the Alliance side. Both teams made middle table finishes, with Spencer Hargrave winning the Alliance Player of the Year.

On the transfer front, the club had tried to sign John Duffy, Warrington scrum-half, but the effort was unsuccessful. Centre Paul Bell was actually signed from Melbourne but injury led to the contract not being fulfilled.

Representatives

Dean Ellis and Peter Reilly were in the Yorkshire Academy squad
Andy McNally and Peter Reilly were picked for Great Britain Young Lions Academy squad
Lee Harland, Francis Maloney, Danny Orr, Darren Rogers, Dean Sampson and Nathan Sykes played for England
Gael Tallec played for France
Darren Shaw played for Scotland (despite not yet playing for the club, having signed for 2000)

Debut this season after joining the club

Aaron Raper hooker Parramatta Australia
Dale Fritz second row North Queensland Cowboys Australia
James Pickering Fijian prop Sydney City Roosters Australia
Michael Eagar Australian centre Warrington
Darren Rogers wing Salford
Brad Hepi New Zealand second row short-term contract from Rochdale
Andy Hill prop Re-signed from York for second stint

Other debuts

Andy Lynch sub forward Castleford Academy

Last career game played this season and next move

Danny Ellison wing released to Halifax
Gael Tallec second row Halifax
Francis Maloney centre Wakefield Wildcats after first stint but returned 2003 for second stint
James Pickering prop returned to Australia
Andy Hill prop York
Spencer Hargrave loose forward York
Brad Hepi loose forward released to Featherstone but signed on loan 2001 for a second stint

Loan Players

Out - Andy Hill prop Huddersfield later returned