[3] Sanchez was hired from Scuderia Ferrari as part of the technical restructure, but was placed on gardening leave until the beginning of 2024;[3] he left the position in April 2024, three months into his contract.

[7] This arrangement posed a major challenge for the team, as parts had to be shipped from the McLaren Technology Centre in Woking, England to Germany in order to be tested.

[14][15] Stella speculated that although the mid-season upgrades delivered to the MCL60 radically improved performance, they may have introduced undesirable handling traits which would have to be investigated during the development of the MCL38.

[18] Further, Stella said that the development programme would prioritise improving tyre degradation, McLaren's main weakness compared to field-leading Red Bull Racing, which would require mechanical as well as aerodynamic changes.

[4] Stella said McLaren's focus was on achieving their development goals rather than a specific result,[20] and said that the team had not hit a point of diminishing returns and found its progress to still be linear and sustainable.

[25][26] Gary Anderson, writing for The Race, concluded that the changes visible on the launch specification car were intended to produce more controlled suspension, improving the MCL38's aerodynamic profile.

[27] McLaren again collaborated with sponsor Vuse to run a special livery featuring the work of a local artist, in this case a design by MILTZ for the Japanese Grand Prix.

[30] A second special livery – in the colours of the flag of Brazil (yellow, green, and blue) – was used for the Monaco Grand Prix to mark the thirtieth anniversary of the death of Ayrton Senna, who won his three World Drivers' Championships with the team.

[31][32] A third special livery inspired by the team's "MP4 era" titled "Legend Reborn" and sponsored by OKX was introduced for the Singapore Grand Prix.

[34] Stella stated that not all the new developments McLaren had planned for the MCL38 had been ready in time for the launch specification car, but would become early season upgrades.

Norris qualified fourth and Piastri sixth for the Australian Grand Prix, and were both promoted a place on the starting grid by a penalty for another driver.

McLaren expected that the car would be uncompetitive at the Chinese Grand Prix given the quantity of low-speed corners at Shanghai International Circuit, in which the MCL38 typically underperformed (see § Assessment and characteristics).

The MCL38 was fitted with circuit-specific beam and rear wings for the Emilia Romagna Grand Prix,[75] and Piastri's car received the remaining upgrades.

[95] For the Grand Prix, Norris qualified second and Piastri seventh, the latter losing his final lap time due to a track limits violation.

McLaren fitted a new rear wing assembly designed for a higher top speed to the car, alongside a different engine cover and cooling arrangement, for the 2024 British Grand Prix.

[114] Norris was overtaken by Piastri on the first lap, and were ultimately beaten by Ferrari's Charles Leclerc who selected a single-stop strategy rather than McLaren's two-stop.

During the Azerbaijan Grand Prix, several observers noted that the MCL38's rear wing was designed to be flexible in such a way that the bottom corners of the upper panel lifted up to allow airflow through.

[119] The Fédération Internationale de l'Automobile confirmed the design was legal under existing regulations but asked McLaren to modify the wing to prevent the flexing, to which the team agreed.

[33] Unusually, the rear and beam wings used were of a low downforce specification, despite Marina Bay Street Circuit typically being considered a high-downforce track.

[134] The stewards judged that his final overtake on Verstappen, which was performed after both ran wide, meant he had gained an unfair advantage, and awarded Norris a five-second penalty that dropped him to fourth place.

[135] Pato O'Ward, a driver for the Arrow McLaren IndyCar team, drove in place of Norris during the first free practice session for the Mexico City Grand Prix.

[142][143] Technical analyst Giorgio Piola and journalist Mark Hughes said the MCL38's superior brake duct design was a key factor enabling Norris to overtake the Leclerc's Ferrari SF-24.

[162] McLaren development driver Ryō Hirakawa replaced Piastri for the first free practice session of the Abu Dhabi Grand Prix.

[163] Norris qualified on pole position and won the race; Piastri finished tenth after being involved in a collision with Verstappen on the opening lap.

[167][168] Compared to its nearest competitor – Ferrari's SF-24 – the MCL38 lacked race pace largely due to the SF-24's superior tyre management, but excelled over a qualifying lap.

McLaren's competitors in the early season, particularly Ferrari and Aston Martin, introduced floor upgrades in pursuit of increased downforce but sacrificed driveability and ultimately lap time as a result.

[183][184] Michael Schmidt, writing for Auto Motor und Sport, noted that every one of McLaren's upgrades since the package introduced to the MCL60 at the 2023 Austrian Grand Prix had worked immediately and as expected.

[186] Commentators have generally agreed the MCL38 has not achieved its best possible results, arguing that a range of strategic errors by McLaren, as well as mistakes by its two drivers, hindered its performance.

[195] Norris's consistently good results after the Miami Grand Prix brought him close to overtaking Verstappen, but the latter's early dominance in the season proved insurmountable.

"[201] Others argued Dennis and Bouiller made their comments before the FIA mandated parity between the engines used by works teams and those supplied to their customers, which began in 2018.