Electrochemical capacitors or “supercapacitors” essentially bridge the gap between traditional capacitors and rechargeable batteries with their high specific power and moderate energy densities. Commercial supercapacitors typically comprise activated carbon (AC) electrodes, which rely on electrostatic double layer charge storage mechanisms. Pseudocapacitors, on the other hand, benefit from surface redox reactions which lend them superior capacitance than their double layer counterparts. Conducting polymers and transitional metal oxides (TMOs) account for pseudocapacitors in general and among TMOs, manganese oxides have widely been investigated owing to their high specific capacitances, low cost, and environmental benignity. In this work, porous manganese oxide (MnO_x) thin films were synthesized via electrostatic spray deposition (ESD) and evaluated as pseudocapacitive electrode materials in aqueous media. Very interestingly, the gravimetric specific capacitance of the ESD based MnO_x electrodes underwent a marked enhancement upon electrochemical cycling, from 72Fg^-1 to 225Fg^-1, with a concomitant improvement in kinetics and conductivity. The change in capacitance and resistivity is attributed to a partial electrochemical phase transformation from the spinel type hausmannite Mn₃O₄ to the conducting layered birnessite MnO₂. Furthermore, the films were able to retain 88.4% of the maximal capacitance after 1000 cycles. Upon verifying the viability of the manganese oxide films for pseudocapacitive applications, the thin films were integrated onto carbon micro-pillars created via carbon microelectromechanical systems (C-MEMS) for examining their application as potential microelectrode candidates. In a symmetric two-electrode cell setup, the MnO_x/C-MEMS microelectrodes were able to deliver specific capacitances as high as 0.055 Fcm^-2 and stack capacitances as high as 7.4Fcm^-3, with maximal stack energy and power densities of 0.51 mWhcm^-3 and 28.3 mWcm^-3, respectively. The excellent areal capacitance of the MnO_x-MEs is attributed to the pseudocapacitive MnO_x as well as the three-dimensional architectural framework provided by the carbon micropillars.