[1] Francisco Comesaña was born in Mar del Plata, Buenos Aires, to father Agustín and mother Adela.

[2] He began his career training at Edison Lawn Tennis in Mar de Plata, which is owned by the family of Horacio Zeballos.

[4][5][6] In May 2022, Comesaña won his first ATP Challenger doubles title in Vicenza, partnering Luciano Darderi.

[11][12] In February 2024, Comesaña made his ATP debut at the Córdoba Open as a wildcard, but lost to compatriot and lucky loser Thiago Agustín Tirante in the first round.

[13] He qualified for his first ATP 500 tournament at the Rio Open, but lost to fourth seed and compatriot Francisco Cerúndolo in the first round.

122, he made his Grand Slam tournament debut at Wimbledon and upset sixth seed Andrey Rublev in the first round in only his second match on grass ever.