On August 1, 1920, a tunnel under Flatbush Avenue opened, connecting the Brighton Line to the Broadway subway in Manhattan.

The two mezzanines at Kings Highway, located directly underneath the subway embankment, were constructed in the original BMT format, but fully renovated in the 1980s, during which two identical sets of porcelain enamel artwork (Kings Highway Hieroglyphs by Rhoda Andors) were installed, one set in each mezzanine.

The one on the north is HEET access only, containing three turnstiles, a staircase to each platform and its MetroCard Vending Machines were installed on the sidewalk.

It was built after the station's opening to accommodate growing passenger flow as evidenced by its newer-style tiling and signage.

It has a token booth, turnstile bank, and two staircases to each platform with the southbound side requiring a short walk.