Driven by his passion for tennis, he aimed to build a career as a professional player, setting long-term goals such as breaking into the Top 100 worldwide.

By 19, Guinard sought to obtain a state diploma (Diplôme d'État en France) to qualify as a tennis coach while simultaneously working on his competitive career.

He joined the Tennis Elite Team (TET) project in Saint-Malo, led by Christophe Cazuc, to support his progression on the professional circuit.

[2] At the 2020 French Open he reached the second round for his first Grand Slam win in doubles also as a wildcard partnering Rinderknech.

In March, he won his maiden singles 2022 Challenger di Roseto degli Abruzzi II title as an Alternate.

In April, he made his ATP debut as a lucky loser at the 2022 Barcelona Open Banc Sabadell where he lost to Hugo Dellien.

In May, Guinard was awarded wildcards into the main draw of the 2022 French Open in singles and doubles partnering Enzo Couacaud.

Guinard reached his first ATP final with Jacq at the 2024 Swedish Open defeating defending champions and top seeded pair of Aleksandr Nedovyesov and Gonzalo Escobar.

[20] In November 2024, Guinard played his first ATP Tour singles tournament in more than two years by entering the main draw of the 2024 Moselle Open as a lucky loser, losing in the first round to Zizou Bergs.