Complex sentence: Working with Trapper was an aspiring young professional named Dr. George Alonzo "Gonzo" Gates (Gregory Harrison), who had a lot in common with Trapper, having also served in a MASH (albeit during the later Vietnam War).
Split into simpler sentences: Working with Trapper was an aspiring young professional named Dr. George Alonzo "Gonzo" Gates (Gregory Harrison). Gates had a lot in common with Trapper, as he too had served in a MASH (albeit during the later Vietnam War).