The German began the final round with an eight shot advantage over Canadian Rick Gibson, and despite considerably windier conditions than the previous three days, he extended his advantage by a further five shots, setting a new record for the biggest winning margin in The Senior Open Championship, beating Bob Charles's 1989 benchmark by six strokes.
He also equalled the second biggest winning margin in Major Championship history, just two shy of Tiger Woods' record 15 stroke triumph at the 2000 US Open Championship, while his winning total of 18 under par 266 was the lowest in the 28 year history of The Senior Open Championship.
In a week when records tumbled, a crowd of 10,539 watched Langer's final round victory march, taking the total attendance for Wales' first Senior Major Championship to 43, 503 "“ the second highest in the history of The Senior Open Championship, just short of last year's record of 45, 503 at Royal Birkdale last year.
They witnessed a player at the very top of his game, with Langer's incredibly winning total made even more remarkable given that only four other players broke par for the Championship, with Montgomerie, who was chasing a third Senior Major Championship, finishing a distant second on five under par following a final round of 69.
Englishman Barry Lane (72), American Tom Pernice Jnr (70) and Gibson (75) shared third place on two under par, but the result was never in doubt as laid-back Langer strolled to his second Senior Claret Jug, following his wire-to-wire victory at Carnoustie in 2010.
"This is very unusual," said Langer, who earns a place in next year's Open Championship at St Andrews. "I've won a tournament by 17, the World Championship under 25 years, but this just doesn't happen, not with the competition you're facing. And certainly not in a Major usually where the best from around the globe are playing in the Championship. So it's been an amazing week for me."
Langer let a two shot lead slip on the 72nd hole at Royal Birkdale before losing in a play-off to American Mark Wiebe in the Senior Open's first Monday finish, but there was never going to be another unusual ending this time round, particularly after he birdied the second and third holes.
A bogey followed on the fourth but he regained that shot on the sixth, then followed a bogey on the 11th with a birdie on the 12th before sealing his comfortable coronation with a tap in birdie on the last.
"I am just very blessed to be able to play such good golf, and I really enjoy the 18 holes today because there wasn't too much pressure," said the two-time Master Champion. "I still had to obviously hit some decent shots and make some putts, but I got off to a great start, and you know, increased my lead and it was a real pleasure to be playing the last ten, 12 holes.
Langer's victory also continues a magnificent sporting summer for Germany, following Martin Kaymer's wire-to-wire victory in the US Open Championship and the national football team's triumph in the World Cup earlier this month.
It led Montgomerie, who extended his lead in the Senior Tour Order of Merit, to pay tribute to the incredible accomplishment of his former Ryder Cup teammate.
"I would like to say, Bernhard Langer's performance here is one of the golfing performances of all time," said Montgomerie. "To finish 18 under round here is remarkable, remarkable play.
"There is satisfaction in finishing second today. The rest of us were playing for second place, and I feel that I won. I won the battle. There were 144 in the field and I beat 143 of them, it was just him. But that him is awfully good, I must admit.
"I've played well here, and I've lost by 13, which is ridiculous. All credit to him."
Spaniard Miguel Angel JimÃƒÂ©nez signed off his debut in The Senior Open Championship with an eagle on the last hole for a round of 68 to finish tied eighth on one over par, while US Ryder Cup Captain Tom Watson closed with a round of 77 to fall back to a share of tenth on two over par.
Peter Fowler did best of the Australians when he finished 21st.
Leading final round scores from The Senior Open Championship Presented by Rolex (par 71)
266 B Langer (Ger) 65 66 68 67,
279 C Montgomerie (Sco) 72 66 72 69,
282 R Gibson (Can) 70 71 66 75, B Lane (Eng) 72 69 69 72, T Pernice Jnr (USA) 78 64 70 70,
284 S Dunlap (USA) 71 73 65 75, B Tway (USA) 67 73 68 76,
285 K Triplett (USA) 72 72 71 70, M JimÃƒÂ©nez (Esp) 74 69 74 68,
286 R Cochran (USA) 74 73 67 72, T Watson (USA) 74 66 69 77,
287 E Toledo (Mex) 73 72 69 73,
288 M Martin (Esp) 74 69 69 76, B Vaughan (USA) 73 69 73 73, F Couples (USA) 71 71 68 78,
289 D Forsman (USA) 72 73 74 70, C Williams (Eng) 68 70 71 80, J Sluman (USA) 73 71 67 78,
290 R Chapman (Eng) 75 73 73 69, S Pate (USA) 75 68 70 77,
291 P Fowler (Aus) 71 72 73 75, D Frost (RSA) 71 76 71 73, P Wesselingh (Eng) 75 73 71 72, M Mouland (Wal) 74 69 75 73, J Spence (Eng) 71 77 75 68, J Hart (USA) 71 74 72 74, R Spittle (Can) 76 73 72 70, O Browne (USA) 72 72 70 77,