Humbert will face Zizou Bergs in Saturday’s men’s final, after the Belgian denied Briton Toby Samuel his shot at glory on home soil.
Samuel, ranked 142nd in the world and who only qualified for the main draw as a lucky loser, had never won a tour-level match before this week.
But, searching for his third straight victory in Eastbourne, the 23-year-old maintained his momentum after stunning world number 45 Juan Manuel Cerundolo in the quarter-finals by taking the first set against the 48th-ranked Bergs.
Seeking to become only the second lucky loser to reach the Eastbourne men’s singles final, and move to the brink of the world’s top 100 having been ranked outside the top 1,000 just 12 months ago, Samuel served for the match at 5-4 in the second set.
But he was broken in that 10th game, and Bergs would go on to clinch a tie-break before eventually completing a 4-6 7-6 (7-5) 6-2 victory.
Saturday’s women’s final will feature American Madison Keys and Germany’s Tatjana Maria, after both players progressed following mid-match retirements by their respective opponents.
Two-time Eastbourne champion Keys, 31, took the first set 6-1 before Croatia’s 20-year-old lucky loser Petra Marcinko decided not to continue.
Meanwhile, 38-year-old tournament debutant Maria, champion at Queen’s last summer, led world number 35 Jelena Ostapenko 6-1 1-2 before the Latvian pulled out through illness.