The MP4/2 lineage was designed by John Barnard alongside Steve Nichols, Gordon Kimball, Alan Jenkins, Tim Wright, and Bob Bell. It used an all-carbon-fibre chassis, one of the first in Formula One, building on the pioneering work Barnard had established with the MP4/1. Power came from a 1.5-litre 90-degree V6 TAG-Porsche turbo engine engineered by Hans Mezger at Porsche, with TAG Electronics funding the entire programme. The engine had been introduced mid-1983 in the modified MP4/1E at the insistence of Niki Lauda, who wanted it race-tested before a championship campaign was attempted.
The original MP4/2 was one of the most dominant chassis in Formula One history. Lauda was joined in 1984 by Alain Prost, who had narrowly missed the 1983 championship. In race specification the engine produced around 650 bhp, rising to 800 bhp in qualifying trim. The car was also among the first to use carbon brakes, though these were less effective than steel brakes at hot or stop-start street circuits such as Detroit and Dallas. Prost and Lauda recorded 12 wins in 1984 — at the time the highest total by a single team in one season — as well as four 1-2 finishes. Lauda beat Prost to the championship by half a point at the final round in Portugal, the closest title finish in Formula One history, despite Prost having won seven races to Lauda's five. McLaren won the Constructors' Championship with 143.5 points to Ferrari's 57.5.
For 1985 the car received cleaner aerodynamics, wings redesigned to comply with new regulations banning rear winglets, and a refined TAG-Porsche engine producing approximately 850 bhp in race trim and 960 bhp in qualifying. A suspension redesign was required after McLaren was forced to switch from Michelin to Goodyear tyres when Michelin withdrew from Formula One. The updated car was designated the MP4/2B.
The competition had more or less caught up. Michele Alboreto in the Ferrari 156/85 contested the championship closely with Prost for much of the season, until McLaren's greater reliability and superiority at high-speed circuits proved decisive. Prost secured his first World Championship with five wins, clinching the title with two rounds remaining by finishing a deliberate fourth at the European Grand Prix at Brands Hatch. McLaren won the Constructors' Championship with 90 points to Ferrari's 82, with Williams-Honda and Lotus-Renault tied on 71. Lauda added one final victory to his record at the Dutch Grand Prix at Zandvoort, finishing just 0.232 seconds ahead of Prost, before retiring from Formula One at the season's end. The result at Zandvoort also confirmed that McLaren operated without team orders on race victory, even where the championship implications favoured one driver over the other.
The 1986 MP4/2C was aerodynamically refined but fundamentally the same package, now paired with Keke Rosberg after Lauda's retirement. By that point the Williams FW11-Honda had become the benchmark car, and the TAG-Porsche engine was producing around 850 bhp in race trim against approximately 900 bhp from the Honda, Renault, and BMW units. Rosberg's driving style — developed on ground-effect cars with late braking — did not suit the MP4/2C's set-up philosophy, which Barnard had optimised for the smoother inputs of Prost and Lauda, and Barnard declined to accommodate Rosberg's preferences until mid-season. Prost nonetheless won four races and took his second championship at the season-ending Australian Grand Prix in circumstances shaped by dramatic tyre failures for both Rosberg and Nigel Mansell.
Across all three variants the MP4/2 won 22 Grands Prix (Prost 16, Lauda 6), took seven pole positions (Prost 6, Rosberg 1), and accumulated 327.5 championship points. The car remains among the most successful chassis in Formula One history.