The 22-year-old lock initially joined the Devon club on a three-month trial in August last year as Baxter looked to bring in sufficient cover whilst club captain Dean Mumm was still recovering from shoulder surgery.
However, the former Leinster Academy player - who spent the 2013/14 campaign playing in France with second tier side Auch, did enough during that time to convince Baxter to keep him on board until the end of this season.
With his contract set to expire at the conclusion of this term, the Chiefs have moved swiftly to ensure Sexton - the younger brother of Ireland and British Lions fly-half, Jonathan Sexton - will remain at Sandy Park for another year at least.
Commenting on the deal, head coach Baxter said: “With the injury situation we had earlier this season with our back five, we needed to bring some extra people in. We had a look at Jerry on a short-term deal and he did very well for us in some A-League games.
“Not only that, but I think he did very well for us in training and created some strength in depth in training which we really needed. Since then he has slowly pushed in from there, bedded himself in, worked hard and put in some good performances in the LV= Cup.
“That in turn has put him on the fringes of the first team squad a couple of times, so what he has shown is enough development from our perspective that he is worthy of another year. The opportunity is now in his hands to keep developing and keep improving as a player and force his way up the pecking order.”
As well as helping the Chiefs to reach this year’s LV= Cup final, narrowly missing out to Saracens with the final kick of the game at Franklin’s Gardens, Sexton also made his Aviva Premiership debut in the narrow home defeat to Gloucester back in early January.
Baxter continued: “When we brought Jerry in we looked at him as an academy-type player and in those terms he has done pretty well – well enough to offer him another deal and see how he keeps developing.
“You need good numbers of decent front-five forwards as you get through quite a few in a year and I think Jerry has done very well for us in the LV= Cup. We want to keep hold of him and see how he develops.
“I think like any player as they start to get a bit older, what he has to show is some continued development. He doesn’t suddenly need to become a Premiership star straight away or a stand-out player here – what he need to show is that he is capable of becoming a Premiership squad player and a Premiership starter occasionally.
“What he has to do, just like any other academy player, is not become a world-beater overnight. The likes of Jack Nowell, Henry Slade, Sam Hill and Dave Ewers did not come out of nowhere, there were levels of progression in what they did and that is what we want to see form Jerry.
“We want to see step-by-step progress from him if he is going to become what we call a senior squad member. That is what I want to see – a good level of progression, see him improving in everything he does, from conditioning to performances on the pitch and then we can assess thing as we go.”