Whatever additional validation Garcia (26-0, 16 KOs) felt he needed surely came as he gritted out a bloody and tough, 12-round decision over the 35-year-old Judah (42-8, 29 KOs.)
Garcia dominated the first two-thirds of the fight and dropped Judah to the mat with a right hand in the eighth round, but Judah rallied in the last three rounds.
The final scoring was 116-111, 114-112 and 115-112.
"I knew [Judah] had a lot of pride behind him and he was never going to give up," said Garcia, who also staggered Judah several times in the fight. "I had to beat the Brooklyn guy in his hometown. He is a crafty veteran with power and he hit me with a good shot. He's been in fights before. He came back strong in the late rounds.
"It shook me up a little in the 11th. Judah is the craftiest and strongest guy that I have fought so far. I am a true champion and I had to fight through a storm to prove that."
The entertaining fight, which had the crowd of more than 13,000 on their feet, was an appropriate end to a week of prefight chaos between Garcia and Judah.
On Tuesday, the entourages of the fighters forced the ending of an autograph-signing session when they exchanged hostile words and nearly came to blows in a Modell's store across the street from the Barclays Center.
Judah went off on fight promoter Oscar De La Hoya on Thursday when he was not allowed to attend a news conference at the same time as Garcia.
"As you can see, it's a lot of bad blood," Garcia said. "I've got cuts. [Judah] has cuts. But it's gone. It's respect.
"We came here to Brooklyn and gave the people a nice show."
Judah, who had vowed that Garcia was "going to sleep," had nothing but praise for the young champion afterward.
"You win some, you lose," Judah said. "Danny is a young, tough fighter. I was on my A-game and I worked hard. We gave it our best shot."
Boxing is a balance-beam sport where popularity and marketability can rise or fall based on the results of single fight.
Garcia's eye-opening run, which started with a unanimous decision over former WBA, WBO and IBF lightweight champion Nate Campbell in 2011 definitely has him riding the crest of wave trending upward. Garcia earned $1.25 million, his second consecutive million-dollar payday, to set himself up as the man to beat in the light welterweight division.
The win will help Golden Boy Promotions to maximize Garcia's marketability.
Garcia's aggressive style, power and sometimes shaky defensive skills lead to exciting and entertaining fights.
You get your money's worth at a Garcia fight.
Although he is American, Garcia's demonstrated pride in his Puerto Rican heritage is getting him accepted as a champion for the large and important Hispanic boxing audience.
On the horizon could be a fight with the winner of the scheduled IBF light welterweight fight between champion Lamont Peterson and No.-1 ranked Lucas Matthysse of Argentina on May 18 in Atlantic City.
Another lucrative fight might be a rematch against Kahn, who beat Julio Diaz in a lightweight fight Saturday in Sheffield, England.
"I'm still learning on the job," Garcia said. "I'm learning every day. I'm getting smarter.
"Every time I step in the ring, I have to keep learning and get better."
There is no flying under the radar for Garcia. Any fighter who doesn't give him his full respect does so at his own peril.