It may sound strange but you can be successful at boxing even if you started at age 25 or later. Few examples Jameel McCline started at 25 Davvaryl Williamson started at 25, too Ray Austin started at 27 Tony Thompson started at 25 or 26 and, of course, Ron Lyle after 25 All of them were good enough to beat few TOP-10 HWs and all of them were world title challengers. Lyle was the most successful of them I think. Anyway, their examples show that you if you have the talent, you can start as late as 25 and still reach TOP rankings.
Leonard "The Lion" Dorin started at Pro Career at 27 having a record of 22-1-1 In 1997, Doroftei became a professional boxer, signing with the Canadian club Interbox. On 5 January 2002 he won the WBA world lightweight title, winning in a split decision over Argentinian boxer Raul Horacio Balbi. On 31 May the two fought again in Bucharest; this second fight was a unanimous decision for Dorin A lightweight title unification bout on May 2003 with American boxer Paul Spadafora, the IBF champion, ended in a draw, 114-114, 115-113, 114-115. Most watching that fight thought Dorin was robbed. [yt]6EaEgJPIHJo[/yt] On 24 October 2003, Doroftei was to fight a match against Panamanian boxer Miguel Callist. Doroftei had already announced that this would be his last professional match regardless of the result. As it turned out, the match was cancelled after Doroftei exceeded the maximum weight for lightweights at the weigh-in: he was 4ΒΌ lb (1.9 kg) over the 135 lb (61.2 kg) weight limit, so he lost his WBA title. On 24 July 2004, Doroftei lost his undefeated mark when he tried to get the interim WBC title, getting knocked out in two rounds by Arturo Gatti.
During his career Dorin was rummered to fight Mayweather Jr. in unification of WBA and WBC but it never happen because the money weren't right.
Dorin had 254 amateur fights and was in two olympics. m Amongst smaller guys, the only ones I can think of are Nate Campbell and Mundine.
Looking for amateur records in Venezuela is a challenge, but Luis "Lumumba" Estaba defeated Francisco Rodriguez, reportedly for the national amateur title at 108 in 1964 at age 26. Rodriguez would go on to win Venezuela's only Gold Medal at the 1968 Olympics, and finish with a 266-4 amateur record. (Estaba himself says he had 127 amateur bouts.) Estaba turned professional at 29, won the WBC Light Flyweight Championship at age 34, and defended it successfully a dozen times. Officially, he was born on August 13, 1938. However, rumors abounded when he was champion that he was actually 40 years old when he won his title, and that he was lying about his age due to Venezuela's mandatory retirement age of 40 for boxers. He claims today that he did indeed lie about being younger than he really is. Jess Willard started boxing when he was 27, and was 33 when he dethroned Jack Johnson in Havana. He was coming off over three years of inactivity at age 37 with 25 bouts behind him when he lost the championship to 24 year old Dempsey, already a veteran of 60 fights. He may well be the least experienced and latest starting boxer inducted into Canastota, factoring in that he had no amateur career.
I thought Amateur Career doesn't count. Thought he meant boxers that started late Pro career, not boxing altogether.
The best so far may be Luis Ortiz, the current WBA regular champ. He was a month shy of his 31st birthday when he turned pro in 2010.