The forward netted once in 11 appearances on loan from Salford City for the Pilgrims when brought in on loan by Craig Elliott in the 2017-18 campaign.
Beesley's only Pilgrims goal was an important one personally, helping Boston defeat the Ammies' National League North title rivals Harrogate Town, Salford clinching the title a week later.
The 25-year-old has agreed a three-and-a-half year contract at Bloomfield Road, with the club also holding the option to extend it by a further year.
Beesley has scored 12 goals in 26 games for League One Rochdale this season.
His father Paul Beesley spent a season (1999-2000) as a defender with Blackpool.
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