Now he has caught Mark McGwire and rekindled this remarkable race for one of the most glamorous and prestigious records in all of sports.
Sosa hit his 61st and 62nd homers Sunday, sending tears streaming down his cheeks and Wrigley Field into euphoria.
Then the man who once sold fruit, shined shoes and washed cars in his native Dominican Republic promised that "this is not over yet."
"I'll let you know when the year is over," Sosa said when asked how many he thought he could hit.
And after four homers in three days against the Milwaukee Brewers, his favorite pitching staff for long balls, Sosa might indeed be ready to jump ahead of McGwire.
Hours after Sosa's stunning performance, McGwire was removed from a game at Houston because of back spasms. McGwire is 1-for-14 since breaking Maris' record with No. 62 last Tuesday night against the Cubs in St. Louis.
"It's awesome, outstanding," McGwire said of Sosa. "I've been doing this for the last few years with Ken Griffey. We go back and forth.
"We've got until the 27th of September. I don't think you have to be a rocket scientist to figure out it's not over. I never once thought that was it."
When the Cubs beat the Brewers 11-10 on Sunday on Mark Grace's two-out homer in the 10th, Sosa stood in the on-deck circle, denied another at-bat and shot at No. 63.
"I thought pretty much the home run race was going to be McGwire's. But when my buddy gets hot, he can hit them in a hurry. And he proved that," Grace said after jokingly apologizing for robbing Sosa of another at-bat.
"I just hope Sammy gets the attention he deserves. Not only has he hit 62 homers, but he has carried us. He is without a doubt the MVP of the National League."
Sosa, who trailed McGwire 24-9 in late May, homered off Bronswell Patrick in the fifth inning, sending an 0-1 pitch 480 feet into the street behind the left-field fence. He hit another 480-foot homer in the ninth, a solo shot off Eric Plunk.
That one dropped Babe Ruth into fourth place on the single-season list with 60, which he hit in 1927. Maris passed that mark with 61 in 1961. Now, amazingly, a record that had stood for 37 years has been passed twice in less than a week.
"It's unbelievable. It was something that even I can't believe I was doing," Sosa said after his ninth and 10th homers off Milwaukee pitching. "It can happen to two people, Mark and I."
With tears and sweat running down his face as he sat in the dugout after his second triumphant tour around the bases, Sosa came out for three curtain calls. Fans littered the field with paper cups and other debris while chanting "Sam-mee! Sam-mee!" causing a delay that lasted six minutes.
"I don't usually cry, but I cry inside. I was blowing kisses to my mother, I was crying a little bit," Sosa said.
"I have to say what I did is for the people of Chicago, for America, for my mother, for my wife, my kids and the people I have around me. My team. It was an emotional moment."
Randy Maris, one of Roger's sons, phoned to congratulate Sosa.
"He wished me good luck and said he was going to watch me," Sosa said.
Commissioner Bud Selig, who was in St. Louis last week for McGwire but not at the Cubs game, also phoned. The Rev. Jesse Jackson and comedian Bill Murray were at the game to offer congratulations.
Fans stayed in Wrigley Field long after the game. Sosa, on his way to meet the press, crossed the field and stopped in front of the pitcher's mound and stopped to wave his cap.
He also sent a message to McGwire.
"Mark, you know I love you. It's been unbelievable. I wish you could be here with me today. I know you are watching me and I know you have the same feeling for me as I have for you in my heart," he said.
Sosa then used his trademark heart thump and said, "That's for you, Mark."
Both of Sosa's homers cleared the back fence at Wrigley Field, sending fans scrambling for balls worth tens of thousands of dollars to memorabilia collectors.
"I'm not much of a sports fan," Plunk said. "That's cool that Maris' record was broken, but it's just one more than 61. That's all."
After the first homer, a parade of fans raced after the ball as it went down the street. Sosa, meanwhile, rounded the bases pumping his fists as the sellout crowd began stamping its feet.
By the time Sosa struck out in the seventh, the street was filled with fans. When he hit in the ninth with the Cubs trailing 10-8, they were chanting "62! 62!" _ and Sosa didn't disappoint them.
Home run ball No. 62 was caught by a man whose identity was not immediately known. Police officers surrounded him and took him to the closest station for his own protection.
"We got him out of there because we thought he was going to get his behind kicked," Sgt. Mary O'Toole said.
The man's plans for the ball were not immediately known. The fan and groundskeeper in St. Louis who got McGwire's home run balls Nos. 61 and 62 gave them to the slugger, who gave them to the Hall of Fame.
The ball Sosa hit for No. 61 was retrieved by John Witt of Dixon, Ill., who stuffed it in his pocket and promised to negotiate with him.
Witt was sitting in a van off Kenmore Avenue outside the stadium, watching the game on a small TV when he saw Sosa swing. He got out of his van and the ball bounced a couple of times and landed at his feet.
"I didn't think I had a chance," he said. "It's an unbelievable feeling. ... How do you know how much it's worth?"
Sosa's bat and jersey were on the way to the Hall of Fame. He was on the
way to San Diego, hoping to keep his homer binge going and help the Cubs
keep their one-game lead in the NL wild card.