A former manager is an ideal person to ask for a letter of recommendation when you're applying for a new job. That is, of course, provided you had a good working relationship with the individual and left your previous position on good terms. Don't attempt to get a recommendation from a former supervisor who put down your work, behaved in a passive-aggressive manner or who might give you a mediocre appraisal.
Call the Manager
Place a personal phone call to your former manager, reintroduce yourself, if necessary, exchange pleasantries and ask for the recommendation. “I’m applying for a job as a graphic designer with ABC Company. They're interested in hearing about the work I did with you last year, in particular, the new rebranding campaign we collaborated on. If you would write a letter that describes my involvement in that project, it would be greatly appreciated.” It's good if you've maintained professional contact since leaving your position, but even if you've drifted apart, providing recommendations for former employees is an accepted part of most management positions, so you should be comfortable making the request.
Send an Email
While slightly less personal, an email is a good way to ask for a job recommendation because it allows you to define, in writing, the job you're seeking, the type of recommendation you need and when you need it. “I made the final round of interviews with ABC Company for a graphic design job. A lot of the position involves rebranding corporate images, and I’d like for the hiring manager, John Smith, to talk to you next week about my skills, if you’re comfortable with that approach.”
Get It In Writing
In addition to using people as references or asking them to take a call on your behalf, you can also ask a former manager for a letter of recommendation. You might opt for a general recommendation that focuses on your career-related skills, which you can reuse in different job application processes. You can also ask for a letter addressed to a specific person in regard to a specific job.
Before you approach anyone about a reference, make sure that person is likely to give you a positive review. Sometimes job seekers list past supervisors as references without asking permission and that manager is caught off-guard when contacted. Also, it's not a good idea to ask a manager at your current company to be a reference while you’re still employed. This is unprofessional and will not sit well with either your current or prospective employer.