The C-terminal electrophilic activation of peptides by alpha-thioesterification requires strongly acidic conditions or complex chemical manipulations) which ultimately limit functional group compatibility and broad utility. Herein, we report a readily accessible N-mercaptoethoxyglycinamide (MEGA) solid-phase linker for the facile synthesis of latent peptide alpha-thioesters. Incubating, peptide-MEGA sequences with 2-mercaptoethanewlfonic, acid at mildly acidic pH yielded alpha-thioesters that were directly used in NCL without purification. The MEGA linker yielded robust access to thioesters ranging in length from 4 to 35 amino acids, and greatly simplified the synthesis of cyclic peptides. Finally, the high utility of MEGA was demonstrated by the one-pot synthesis of a functional analog of the Sunflower Trypsin Inhibitor 1.