Embodiments of a wireless communication device and method for multi-MCS OFDM transmissions at different transmission power levels are generally described herein. In some embodiments, the wireless communication device may have a multi-MCS OFDM transmitter that is configured to encode data for transmission over two or more RF channels with a single encoding scheme to generate an encoded data stream. The transmitter may segment bits of the encoded data stream into a bit stream for each of the RF channels based on a selected modulation level for each of the two or more RF channels. A separate time-domain multicarrier waveform may be concurrently transmitted on each of the two or more RF channels at a power level that is selected not to exceed a maximum allowable transmit power level for that RF channel. The modulation level for each RF channel may be selected based at least in part on the maximum allowable transmit power level for that RF channel.