Montgomerie is a member at Royal Troon, where his father James was secretary, and will play at the Open for the first time since his 21st consecutive appearance in 2010.
He came 24th at Troon in 1997 and 25th in 2004. His best British Open was as runner-up to Tiger Woods at St Andrews in 2005.
"If I was going to play one Open, it would be this one as my qualifying days are behind me after this," said Montgomerie. "I'll never play another at Troon because it comes back, what every 12 years, and I'll be gone by then.
"So this gives me an opportunity to play and I think I can say this meant more to me than, with all respect to everyone else, to anyone else playing here."
Irishman Paul Dunne also booked a place at the Open after leading the qualifiers at Woburn while Matthew Southgate earned his spot in qualifying at Royal Cinque Ports a year after treatment for testicular cancer.
Dunne shared the 54-hole lead at last year's Open before finishing tied for 30th, nine shots behind winner Zach Johnson.
The final qualifying spots at Woburn went to Ryan Evans and European Tour veteran Robert Rock, who tied for seventh in the Open at St Andrews in 2010.
Also advancing from Deal with Southgate were England's James Heath and New Zealand's Steven Alker.
England's Jack Senior led the qualifiers at Hillside with Boston professional Dave Coupland coming through a five-way playoff, along with Paul Howard who took the final spot.
(Writing by Ken Ferris; Editing by Mark Lamport-Stokes)
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