This season his performances in the championship - he is the country's leading wicket-taker with 61 at 19.44 runs apiece - have done much to keep Gloucestershire in the tight group of teams near the head of the table.
Today Gloucestershire lie second in the championship, after narrowly defeating the leaders, Surrey, at Cheltenham. Walsh was again hugely influential, taking six for 47 in Surrey's second innings and nine wickets in the match.
With seven games left Walsh, who will not play for Jamaica in the Commonwealth Games in September, could reach 100 wickets for the second time in his career.
Walsh's enthusiasm for the game remains as great as ever despite a schedule which, since he first toured here with the West Indies in 1984, has encompassed 102 Test matches, bringing him 375 wickets, and 185 one-day internationals, yielding 204 wickets. In addition, since becoming Gloucestershire's overseas player in the latter part of the 1984 season he has bowled around 5,800 championship overs for them, taking 804 wickets, which means an average of 80 victims per season, for an average just over 20. At Walsh's time of life some cricketers might be relaxing a little but he is still looking to develop his bowling.
His county captain, Mark Alleyne, explained the recent appearance of a Franklyn Stephenson-type slow ball in the Walsh armoury. ``It started at nets early this season,'' he said, ``when Courtney and our bowling coach, Bob Cottam, were talking about variety in bowling.
``They had their heads together for a while, then Courtney had a bowl. He slipped in the slow one and, as it happened, pitched it. The stumps went over and there he was, the old pro, jumping about like a 17-year-old.''
Here is Walsh, a veteran with massive achievements, still looking to improve. What a lesson for one or two much younger bowlers who seem to think they have nothing left to learn.
In Walsh's early years with Gloucestershire his then captain, David Graveney, remarked how difficult it was to get the ball off him, no matter how many overs he had bowled.
Alleyne still has the same problem. ``I think that I ought to be careful with him these days,'' Alleyne said recently. ``So I'm looking to bowl him in spells of five or six overs at most.
``But he keeps walking up from long leg with his finger in the air, saying 'one more, one more'. He finishes up bowling eight or nine. He is enjoying the contest as much as ever.''
How long will Walsh continue? He is keen to pass Malcolm Marshall's tally of 376 to become the West Indies' leading wicket-taker in Tests, but after that he has, characteristically, not committed himself. As Alleyne says: ``Courtney always likes to keep his options open.''
This year he has a testimonial, offered with gratitude by his county six years after his benefit. Two things are certain: 1, that no overseas player has ever worked harder, more willingly or more effectively; 2, that as long as Courtney Walsh has a cricket ball in his hand batsmen will be facing a subtle, hostile and unrelenting opponent.