He was baptized at the age of 15 by John Russell, the minister of an Arminian Baptist church at Chesham, Buckinghamshire.

Keach developed Calvinist soteriological views following his move to London, and he became a Reformed (or "Particular") Baptist.

[4][1] As a representative of the Horsleydown church, Keach attended the 1689 General Assembly that endorsed the 1689 London Baptist Confession of Faith.

The people, contrary to custom, had no words of mockery for the good, persecuted minister, and no offensive missile was hurled at him.

An Episcopal minister who ventured to assail Mr. Keach in the pillory was immediately reproached by the people with the ungodliness of his own life, and his voice was drowned in laughter.

At Winslow, where he lived, he suffered the same shameful penalty, and a copy of his little book was burned.Keach is also known to have promoted the introduction of hymn singing in the Baptist churches.

Keach's hymnbook, published in 1691, provoked heated debate in the 1692 Assembly of Particular Baptists, as it conflicted with the position of exclusive psalmody.

[1] Also among his eschatological convictions, Keach anticipated a major revival amongst the Jews at the end of the present age.