The Reds, who only survived relegation on the final day of last season and were in deep trouble when the Frenchman was appointed head coach in October, secured fifth place courtesy of Saturday's 2-2 draw with champions Norwich City.
That result sets up a play-off semi-final showdown with Swansea City, but whatever the outcome of that two-legged affair, it is undeniable that Ismael has worked something of a miracle at Oakwell this term.
"To analyse the season, I think it is an incredible achievement to be fifth after 46 games in the Championship," the 45-year-old former Bayern Munich defender said.
"When you see where we started and what happened last season, there's been a commitment from the players on the pitch, they are dedicated to the principle of the way to play football.
"I am just grateful tonight to be manager of this team, the commitment from everyone so far this season has been incredible. It is good to see that when you are ready to invest and believe in something, you can achieve great results.
"We are really proud to give this season to the fans and I really hope we can get a big, big reward with the first leg [of the play-off semi-final] at home with fans because we need to celebrate with the fans."
Saturday lunchtime's final-day clash with table-topping Norwich saw Barnsley delivered a much-improved performance compared to what has been served up in recent weeks.
The Canaries could not live with their hosts' intensity during the opening 45 and found themselves trailing 2-1 at the break to goals from Cauley Woodrow and Conor Chaplin.
And although City pulled level in the second period before going on to finish the stronger, Ismael believes that his team's display proved just how good a side they have developed into.
"We were back to our strengths, back to our identity and I think it was important for us to finish strong against the champions," he added.
"We wanted to win, we wanted to perform and I think we deserved at least one point against a quality Norwich team. Congratulations to them, they deserved to be champions.
"We saw today their quality and that is why I am proud of the guys because they gave such a performance agains them again. It is a great feeling to see that we are a top team.
"We showed today why we finished in a play-off spot."