Mayer is expected to be formally announced in the position on Monday after holding the role of general manager of commercial operations since October last year.
The Tigers are on the lookout for a new chief executive and Mayer will run the club on an interim basis once Stephen Humphreys leaves the post.
''Grant will be the ultimate go-to man in terms of day-to-day administration,'' Tigers chairman Mike Bailey said. ''There are many things we need to consider as a football club, including sponsorship, etc, and he will have to step into the main role even though he won't be stepping into the chief executive's role.''
Mayer has extensive experience in sports administration. He was the chief executive of the Sea Eagles when they tasted premiership success, held a senior position at the Bulldogs and spent almost three years at the GWS Giants as their general manager of commercial operations.
''The board has shown some faith in me and given me a great opportunity to help the club,'' Mayer said. ''The fact I've done it before, at CEO level at a couple of clubs, means it's nothing new to me and I'm looking forward to the challenge.''
Mayer's priority will be to find a replacement for Humphreys, and the board is likely to sign off on the recruiting process this week. There are plenty of other challenges for the bottom-placed club, including recruitment and retention. He said one of his priorities would be to resolve the long-term future of star playmaker Benji Marshall.
''There are three Rs in rugby league - retention, recruitment and revenue,'' Mayer said. ''That's what I will be focusing on in the next period, making sure we get that right. The fans have been exceptionally patient and I can assure them is they'll get my 100 per cent commitment while the board goes through the process.
''You can probably add an extra 'R' and that's resilient, which is exactly what the Tigers fans are.''
Mayer, who worked with Mick Potter during a stint at the Catalans Dragons, believes the coach can turn the club's fortunes around in his debut NRL season. ''Knowing Mick as I do, he's been around coaching and football for a long time and he understands the situation,'' he said. ''It is a process and he's come on board at a time when the coaching group and the football team itself has been put together by his predecessor. He's also suffering injuries like no other club before. He's got his own challenges but he is certainly up to the challenge.''