<b>(</b><i><b>R</b></i><b>)-7</b> [<b>(</b><i><b>R</b></i><b>)-AS-1</b>] showed broad-spectrum antiseizure activity across <i>in vivo</i> mouse seizure models: maximal electroshock (MES), 6 Hz (32/44 mA), acute pentylenetetrazol (PTZ), and PTZ-kindling. A remarkable separation between antiseizure activity and CNS-related adverse effects was also observed. <i>In vitro</i> studies with primary glia cultures and COS-7 cells expressing the glutamate transporter EAAT2 showed enhancement of glutamate uptake, revealing a stereoselective positive allosteric modulator (PAM) effect, further supported by molecular docking simulations. <b>(</b><i><b>R</b></i><b>)-7</b> [<b>(</b><i><b>R</b></i><b>)-AS-1</b>] was not active in EAAT1 and EAAT3 assays and did not show significant off-target activity, including interactions with targets reported for marketed antiseizure drugs, indicative of a novel and unprecedented mechanism of action. Both <i>in vivo</i> pharmacokinetic and <i>in vitro</i> absorption, distribution, metabolism, excretion, toxicity (ADME-Tox) profiles confirmed the favorable drug-like potential of the compound. Thus, <b>(</b><i><b>R</b></i><b>)-7</b> [<b>(</b><i><b>R</b></i><b>)-AS-1</b>] may be considered as the first-in-class small-molecule PAM of EAAT2 with potential for further preclinical and clinical development in epilepsy and possibly other CNS disorders.