The Turnhouse member is among six Scots included in an initial squad of 26 players selected by the R&A in the battle to make the Great Britain & Ireland team set to face the United States at Royal Liverpool in September.
McIntosh joins Euan Walker (Kilmarnock (Barassie)), Sandy Scott (Nairn), Kieran Cantley (Liberton), Jamie Stewart (Old Ranfurly) and Ryan Lumsden (Royal Wimbledon) among the hopefuls for a 10-man team being captained by Craig Watson.
While the oldest player in the squad by some 24 years, McIntosh has earned his chance after enjoying a successful spell since he was reinstated to the amateur ranks following a ten-year break from the game.
He topped the Scottish Order of Merit in 2016, the same year he returned to the international arena after a 27-year gap, before winning the Scottish Amateur Championship last year at 49 - the oldest player to claim that title in 35 years.
“I did not expect it, to be honest,” said McIntosh of his selection. “I got an email on Tuesday to let me know I was in the squad and it is great. In fact, it is fantastic.
“A lot of people will probably look at it and say, ‘wow, picking a 50-year-old’, but good on the selectors for including me among all the young lads.
“Based on my results last year, I think I probably deserve to be in the squad. I never missed a cut in the big amateur events and I was competing.”
The chance to become one of the oldest Walker Cup players in the event’s history has come after McIntosh put his plan to turn professional for a second time in his career on hold after failing to secure a foothold on either the Champions Tour or Staysure Tour this season.
He’s set to try again for next year but, in the meantime, his focus is on impressing at a squad session at Royal Liverpool next week, after which the number of players in contention will be reduced for a second get-together at the Merseyside venue in July.
“Being in the squad is one thing, but to make the team I think I will have to play the best golf of the year,” said McIntosh, who was based in Germany during his spell in the professional ranks.
Referring to the Walker Cup format, he added: “Foursomes is tailormade for me. I don’t really hit it off line and my iron game is normally strong. If I did manage to play great all year and get picked, I know that I could do a job in foursomes.
“Singles? When you are playing against these young kids, you just have to go out and blitz it because that’s what they do.”
Walker won the African Amateur earlier this year, while Scott’s selection comes after he capped a good spell on the US college circuit by triumphing in the El Macero Classic earlier this month.
A dozen English players include Boys Amateur champion Conor Gough and Alex Fitzpatrick younger brother of European Tour player Matthew, while a five-strong Irish contingent is headed by Conor Purcell, who won the Australian Amateur earlier this year, and 2018 St Andrews Links Trophy victor John Murphy.
“We have selected a talented group of players and will be continuing to monitor the form and results of these players over the course of the season,” said Watson.
“We will also be looking closely at the performances of other players who have not been included in the squad and there is still time for them to play their way into our plans ahead of the final team selection later this year.”