Expanding, we get:

\\[\Gamma(t) = e^{t H} \Gamma(0) = (I + tH + \frac{1}{2!} t^2 H^2 + \cdots)\ \Gamma(0) = \Gamma(0) + tH\ \Gamma(0) + \frac{1}{2!} t^2 H^2 \Gamma(0) + \cdots \\]