The on-loan Wigan defender, along with Fulham striker Marcello Trotta, both made their debuts in Saturday's win over Sheffield United.
"There's a great spirit here," he told West London Sport. "The new faces, including me, have been able to get into the swing of it quickly and we could see how much everyone was up for the Sheffield United game."
Kiernan, who is traditionally a centre-back, has impressed in midfield covering for the suspended Jonathan Douglas.
"I haven't played there (midfield) for years - since my Watford Under-16s days actually," he added. "I thought I did okay. I was happy with my contribution to the first goal.
"I love it here at Brentford. I'm back home living in Watford and I feel much happier in myself."