He amassed 275 runs in 5 matches against South Africa on the 1938/39 MCC tour, including a score of 112 in 2 hours, 40 minutes in Cape Town in the Second Test of the series.

His long career at Kent County Cricket Club as a right-handed batsman and occasional medium pacer spanned two decades from 1927 to 1948.

He was awarded his Kent cap in 1931 and captained the county on occasion during the 1930s in the absence of Percy Chapman; in 1937 he shared the captaincy with Ronnie Bryan.

An attacking batsman whose defence improved with experience in the first-class arena, he was particularly strong through the leg side but his Test appearances were limited by the strength of the England team at the time.

During World War II Valentine served with the Royal West Kent Regiment and was awarded the Military Cross "in recognition of gallant and distinguished services in North Africa".