Mourinho, who is now at Manchester United, gave the 25-year-old his first team debut when the Portuguese tactician was in charge at the Santiago Bernabeu. It was the 55-year-old who promoted Morata to the first team, after the frontman impressed for Real's B team.
"He [Mourinho] treated us very well and cared for us, using a carrot and stick," Morata explained, as quoted by the Spanish publication Marca.
"He gave me my first big contract at Madrid, he called me after a bad training session and said to me that if you started well then you will never have to work in your life but right now you have to decide where you want to go, so work well."
Mourinho was looking to reunite with Morata at Old Trafford last summer. United were pursuing the Spain international, while Chelsea were planning to re-sign Romelu Lukaku from Everton in the same window, according to the BBC.
However, the Red Devils' failure to agree a fee with Real saw them end their interest in Morata and sign Lukaku. This forced Chelsea to change their transfer plan and sign Morata from the La Liga giants.
Morata left Real and made a switch to Juventus in 2014. The 12-time European champions re-signed the striker in 2016, only to sell him to Chelsea a year later.
The Spaniard had expressed his displeasure after he was left out of the starting lineup for the big games by manager Zinedine Zidane. He later stressed that it was one of the reasons for leaving Real last summer.
"I was not asking to be a starter with Madrid, I know that these players are something else, on another planet," the Blues striker said.
"But I didn't play any Champions League ties, a match against Barcelona, against Atletico, Sevilla or Valencia.
"It would have been fantastic to play at Madrid but due to the circumstances it was not possible and that is not the end of the world. Madrid will always be there, I am a fan of Madrid and I watch the Madrid games."