"[McCarthy] is a big name and from what I have seen, and heard from other people, he is a great character. At a time like this, that is what we need," said Loach, who joined the Blues from Watford this summer.
"The results on the pitch have not lived up to the name and history of Ipswich. But I think the fact we have attracted someone of Mick's calibre shows that Ipswich is still a massive club.
"For us, the season has to start today at Birmingham."
Loach fell out of favour with former boss Paul Jewell, who brought in Stephen Henderson on loan from West Ham, but now the 24-year-old feels he has a chance under McCarthy.
He added: "Hendo has come in and he is a great lad to work with in training, along with Arran Lee-Barrett (Ipswich's third-choice keeper).
"All I can do is keep training hard and if the new manager wants to pick me, he will. But I will always give my all."
Ipswich are rockbottom in the Championship, five points from safety.