The influence of energetic electron rings, or disks, on the magnetohydrodynamic stability of an axisymmetric tandem mirror configuration is studied. Linear stability equations describing interchange and ballooning modes are solved both analytically and numerically using a two‐dimensional stability code for axisymmetric mirrors. Finite‐ion‐Larmor‐radius effects and the presence of a lateral wall are included in the calculations. Stable configurations can be obtained with either sufficiently high hot‐electron pressure or with sufficiently high center‐cell pressure if a lateral conducting wall is close enough to the plasma. In particular, hot electrons might be used to stabilize transiently the plasma during buildup to a high‐beta, wall‐stabilized configuration.