Bryson, though a member of the outcast Antrim presbytery, was, as his manuscripts show, a frequent preacher in neighbouring congregations of the general synod.
At the time of the rebellion in 1798 Bryson was a staunch loyalist, in this, as in other matters, following the lead of his co-presbyter, Bruce of Belfast.
In September 1809 his age and infirmities rendered him desirous of resigning his pastorate, but as his people could not agree upon a successor, he did not do so till November 1810.
In the vestry of the First Presbyterian Church, Belfast, hangs a likeness of Bryson, copied by his son Patrick from a silhouette taken in his forty-sixth year.
When about that age he married a daughter of Alexander Maclaine, M.A., minister at Antrim, 1742-59, and granddaughter of John Abernethy, by whom he had six children.