Karl Harrison’s side, who kicked off with a win against champions Sheffield, led 8-6 at the break before going on to record a convincing success.
Halifax made the worst possible start, conceding a try to the home half back Carl Forber inside a minute after the former Castleford playmaker Peter Lupton had broken in midfield.
Forber kicked the conversion, but the visitors drew level when wing Lee Paterson touched down in the right-hand corner from Paul Handforth’s long pass.
Centre Steve Tyrer could not convert and he was off the mark again when he scored Halifax’s second try just before the half hour after back rower Ross Divorty had hacked a loose ball towards the corner flag.
With neither side manufacturing a chance of note before the break, it was Halifax who led 8-6.
The second half was a relentless grind in increasingly poor conditions, with heavy rain discouraging any kind of adventure with the ball.
The decisive moment arrived after 65 minutes when Halifax’s former Batley and Featherstone forward Dane Manning, who was returning from a two-game suspension, raced 40 metres to score and Tyrer kicked the conversion for a 14-6 lead for the visitors.
A fourth try, scored by Tyrer, quickly followed as Halifax opened up a decisive 20-6 lead with 10 minutes remaining.
Workington secured a bonus point with a Forber penalty three minutes from time.
Workington: Carter; Patrick, Hulme, Morris, Calderwood; Lupton, Forber; Dowes, Phillips, Walne, Phillips, Stack, Olstrum. Substitutes: Coyle, Thackray, Gore, Davies.
Halifax: Fieldhouse; Sheriffe, Heaton, Tyrer, Paterson; Handforth, Murrell; Ambler, Ashall, Bracek, Manning, Divorty, Robinson. Substitutes: Tonks, Ashall, Bowman, Casey.
Referee: M Thomason (RFL).