The Tigers have announced the 22-year-old, son of former England international Paul Ince, has agreed a two-year deal at the KC Stadium.
Compensation with Blackpool has yet to be agreed and a tribunal may be necessary if a figure cannot be settled upon.
Ince, who ended last season on loan at Crystal Palace, had attracted interest from a number of other clubs, most notably Serie A giants Inter Milan.
Ince travelled to Italy for discussions with Inter - one of his father's former clubs - but opted to remain in England and look for a Premier League club.
He met with Hull officials last week and a deal was concluded after further talks on Monday.
Ince came through the youth ranks at Liverpool and had a loan spell at Notts County before moving to Blackpool in 2011.
He has been linked with a return to Liverpool on numerous occasions in the past but a move back to Anfield never materialised.
Ince is Hull manager Steve Bruce's third signing of the summer after completing an £8million permanent deal for Jake Livermore from Tottenham and landing Robert Snodgrass for £6million from Norwich.
Bruce is keen to expand his squad ahead of a potential European campaign in the coming season
Hull will play in the Europa League qualifiers after reaching the FA Cup final last term.
Source : PA
Source: PA