The Serb ended an eight-month trophy drought with a vintage display to win 7-6(3), 7-6(2) and complete his career Golden Slam in memorable fashion, not dropping a set in six matches at Roland Garros.
He is the oldest man to win the Olympic singles title since tennis returned to the Games in 1988 and remarkably he did it 21 days after being pummelled by Alcaraz in the Wimbledon final and two months after undergoing knee surgery.
"I won the bronze in my first Olympic Games (2008) and ever since then failed to win the medal and played three out of four Olympic Games in semi-finals and couldn't overcome that obstacle," Djokovic, proudly wearing his medal, told reporters.
"And then now at age 37, with a 21-year-old that is probably the best player in the world right now, winning Roland Garros and Wimbledon back-to-back and playing incredible tennis.
"When I take everything into consideration, this probably is the biggest sporting success I've ever had in my career."
The 24-time Grand Slam champion produced a level of tennis that has been missing this year to fight off Alcaraz.
After belting away a forehand winner to end a ferocious, near three-hour battle, the emotion poured out of Djokovic as he sobbed on court before climbing into the stands to embrace his family, including wife Jelena and son Stefan, and his team.
"Until today I thought that carrying the Serbian flag at the 2012 opening ceremony in London is the best feeling that an athlete could have," he said.
"This kind of supersedes everything that I imagined, that I hoped that I could experience and that I could feel."
Djokovic did not rule out playing at the Los Angeles Olympics in 2028, but said the realisation that Paris was probably his last swing at gold had motivated him.
"I was ready for this tournament and I didn't drop a set the entire tournament," he said. "I knew in the opening two rounds the way I was playing that this is my chance. If it's ever going to be, it's going to be now.
"When I qualified for the finals, I felt a big relief because that's the hurdle I wasn't able to surpass. I did celebrate like I won the tournament. But of course I wanted gold and I knew that I would have to climb the highest mountain there is at the moment, playing Alcaraz."
Djokovic saved eight break points during a match of stunning quality and intensity -- the Serb describing the duel as like few others he had ever experienced.
"I don't think I've ever played, maybe a few times in my life, such a high level for three hours for only two sets," he said. "Credit to him, congratulations to him for a great tournament, great fighting spirit."
