Known as one of the most rugged defenders of his era, he was sent off four times while playing for Small Heath and that at a time when such occurrences were extremely rare. His career at Small Heath ended in March 1895 when he was released after an incident at Derby where, after being ordered from the field, he attempted to assault two spectators. Jenkyns moved to London in April 1895, joining Woolwich Arsenal, who had joined the Second Division less than two years ago. He was immediately made Arsenal captain, and made his mark in Arsenal history by becoming the club's first ever international player, after winning a cap for Wales against Scotland on 21 March 1896.
