The Frenchman is very much a bit-part player at Old Trafford having started just two Premier League matches all season, and will now try to revive his career in LaLiga.
Martial, who earns around £200k-a-week at Old Trafford, told manager Ralf Rangnick he wants to leave the club in December in order to get more playing time elsewhere in December.
He was left out of the squad in Man United's draw at Aston Villa earlier in January but came off the bench to good effect on Saturday, playing a key role in Marcus Rashford's last-gasp winner against West Ham at Old Trafford.
Nevertheless, a new challenge awaits Martial in Spain with an agreement in place for him to move to Sevilla on loan until the end of the season.
Martial will undergo a medical in Seville on Tuesday and put the finishing touches to the switch.
Seville are paying a loan fee of around £6m but there is no option or obligation to make the transfer permanent in the summer.
Martial has helped United to three trophies during his six years at Old Trafford - an FA Cup, League Cup and the Europa League.
He's netted 79 goals in 269 appearances during his time with the Premier League giants.
He's shown glimpses of immense talent and patches of good form, but he's never delivered for the Red Devils for a consistent period of time.