His mother, Rebecca, daughter of David Allen, rector of the neighbouring parish of Ludborough, was educated in Latin, Greek, and Hebrew.
After spending a short time at Queen Elizabeth's High School, Gainsborough, he was sent in April 1620 to Peterborough, to be under Dr John Williams, then one of the prebendaries, and an old friend of his father.
While in statu pupillari he was suddenly called on by the vice-chancellor to act as terræ filius in place of one who was deprived of the office on account of his scurrility.
In July 1630 he accepted the mastership of a school at Kirton-in-Lindsey, but soon moved with some Cambridge contemporaries to London, settling first in Fuller's Rents, and afterwards at Sion College, so as to make use of the library.
The master and fellows of Magdalene College elected him to a by-fellowship on the foundation of Dr Goch, with a promise of the first open founder's fellowship that should fall vacant.
He became a successful tutor, numbering among his pupils two sons of the Earl of Suffolk, with whom he became intimate, and two of Francis Leke, Baron Deincourt.
Rainbowe was consecrated in July 1664, in London, by Gilbert Sheldon, Archbishop of Canterbury, and in September in the same year he arrived at his palace of Rose Castle, near Dalston, in Cumberland.
He had to borrow money to pay for the charges of his consecration, first-fruits, and his journey and settlement in his diocese; and the ruined state of his palace involved him in building, and in litigation about dilapidations with his predecessor and metropolitan, Sterne.
Negligent clergy publicly affronted their bishop, and his outspoken denunciation of immorality appears to have offended some great lady about the court.
[2] Rainbowe died on 26 March 1684, and was buried, by his own request, at Dalston (1 April), under a plain stone, with a simple inscription.