The dual champion jockey was pleased to reach the landmark after enjoying his best season in terms of prize-money thanks to big victories on Taghrooda in the Oaks and King George, and Mukhadram in the Coral-Eclipse for his boss, Sheikh Hamdan Al Maktoum.
And it was for the latter that he took his tally to 101 when completing his threesome on Rewaaya in the inaugural running of the Sir Gordon Richards Handicap at the East Midlands track.
The 7-4 favourite, trained by John Gosden, made it three wins from five starts when beating the veteran Harris Tweed by a length and a quarter, despite hanging to the right in the closing stages.
“She’s done well and loves that ground. It was quite soft when she won here last time. She’s done well and is very tough,” said Hanagan.
“She just started to lug right even before I got to the front.
“Even though she liked the ground it’s quite hard work out there.”
Hanagan reached the century on Gabrial (6-1), who put his best foot forward in the SIS Handicap.
Richard Fahey’s charge has disappointed on occasions, but has been a regular in stronger company and was on a going day as he disposed of God Willing by a length and a half.
“It’s certainly my biggest ever prize-money this year and I’m delighted to do 100 winners for the year. I started quite late, in April.
“I was never in doubt there. They went a nice gallop and he travelled lovely all the way through so I couldn’t knock him today at all.
“He really put his head down for me and tried. He’s been out to Dubai and he’s on the go a while so to put in a performance like that was really good.”
Hanagan had earlier taken division two of the Haymarket Nursery Handicap on Miss Van Gogh (3-1 favourite), also for former boss Fahey.
The rider told At The Races: “She handled the ground quite well.
“They went a decent pace up front and she just warmed into the race nicely.
“The further they went the better.”
The Kevin Ryan-trained Sir Domino (even-money favourite) confirmed the promise of his debut second when shrugging aside his market rival Quintus Cerialis under Graham Lee to lift the British Stallion Studs EBF Maiden Stakes.
Lee completed a short-priced double on 1-4 hot-pot Pastoral Girl in the Cossington Median Auction Maiden Fillies’ Stakes for James Given.
The Group-placed filly got off the mark at the seventh attempt with a workmanlike one-length victory over Paloma Dancer.
Agadoo (6-1) gave Shaun Harris his 39th winner on the Flat this year when running away with division one of the Haymarket Nursery Handicap.
David Probert always had the Multiplex filly handy as Bushtown Boy set the pace before she bounded clear over a furlong out to defeat Red Stripes by a convincing two and a quarter lengths.
The David Evans-trained Swift Cedar (5-2) took the Gumley Claiming Stakes under Silvestre de Sousa, while the Danny Burton-ridden Echo Of Lightning (12-1) was a convincing winner of the concluding Fosse Way Amateur Riders’ Handicap.