The highway is apparently named after Ramón Diokno, a native of Taal, Batangas who served as a representative for Batangas, senator and Supreme Court associate justice.

[4][5] Diokno Highway starts at its intersection with Tagaytay–Nasugbu Road in Calaca, near the provincial boundary of Batangas and Cavite.

Starting from near the foot of Mount Batulao, it runs through the mountainous terrain on the western edge of the Taal Volcano Natural Park, traversing especially Payapa Ilaya and Payapa Ibaba, barangays in Lemery to where its alternate name, Payapa Road, apparently derived its name from.

The origin of the highway could be traced back to 1945, when the US Army Corps of Engineers built a “dusty, twisting, narrow” road between Mount Batulao and Lemery as the shorter route relative to Route 17, which connected Imus and Batangas via Palico in Tuy and includes the present-day Aguinaldo Highway, Tagaytay–Nasugbu Road and Palico–Balayan–Batangas Road.

[8] In August 2016, a 100-meter (330 ft) section of the highway in Calaca was closed to traffic due to road slip and collapsed slope protection following the continuous heavy rains in the area.