When we think of someone putting in long hours on the job, the image is often one of late nights and the proverbial midnight oil. But professionals like Andrew Grumet, 34, a tax lawyer at Herrick, Feinstein, would rather clock many of those hours early in the morning.

Grumet, who works from the firm’s offices in Newark and Manhattan, routinely works 13-hour days, but he is also back home in time to read bedtime stories to his children. He does it by leaving his house at about 5 am, arriving at the office by 6 am and leaving for the day at about 7 pm, which he says is considered early for lawyers.

Grumet has been with the firm for seven years. “At my stage of the game,” he said, “as long as I’m billing hours and my work is perfect, no one is overly concerned with when I put in those hours.”

He hopes to become a partner and says his colleagues know that he works long hours. “I know the first thing everyone does when they wake up is check their BlackBerry, because that’s what I do,” he said. “If I’m at my desk at 6 am and I respond to an e-mail within 30 seconds — from my desktop computer — people notice that.”

Although he is not a morning person by nature, he finds that the quiet, early hours also allow him to work on career and business development projects, like writing articles for tax publications and preparing lectures for national conferences.

Although those who put in extra hours still usually do so in the evening, the situation is changing, said Ellen Galinsky, president of the Families and Work Institute in New York City. As older baby boomers leave the work force and younger workers like Grumet move into senior management, the workday is becoming much less rigidly defined, Galinsky said. “It’s not a revolution but an evolution,” she said. “Generation X and Y have different values and are more family-centric than baby boomers.”

According to the institute’s research, 42 per cent of all working parents rely on each other to provide child care for children under 13. “These are tag-team couples,” Galinsky said.

Face time at work, once considered essential for career advancement, is now less crucial because of technology. “It still matters, but there is now a tremendous variance in how much it matters to individual managers,” said Karissa Thacker, a management psychologist and president of Strategic Performance Solutions in New York. Thacker says managers now equate good performance with “the perception that you are on top of things”.

“More and more I’m hearing, ‘If he were on top of his workload he wouldn’t need to be staying here until 8:30 at night,’ ” she said.

Marjorie Brody, an executive coach and founder of Brody Professional Development in Philadelphia, hears similar sentiments from the executives she coaches. “Often when employees work late all the time, managers ask, ‘Why aren’t they able to get their job done?’ ” Brody said.

Jill Tregillis Bacon, a partner in the audit department of PricewaterhouseCoopers in Los Angeles, switched from a 9 am starting time to much earlier morning hours in 2003, when she was pregnant with her first child. She still works long hours but no longer stays late. Instead, she works most intensely from an office at home from 5 to 9 am before heading downtown or to meet directly with clients. “Those hours became the most productive of my entire career,” she said. “I also noticed how much better my client and staff interactions were after 9 am.” Bacon said she believed that her switch to earlier hours was the critical factor in her becoming a partner at PricewaterhouseCoopers.

Michael Song, chief executive and co-founder of Cohesive Knowledge Solutions, an e-mail management firm in Guilford, Connecticut, has always been an early bird. Before the company started in late 2004, he worked for a decade in pharmaceutical sales at Pfizer and won numerous performance awards.

“I would be in an emergency room at 5 am so I could talk to doctors coming off the night shift and those starting the day shift,” he said. When he moved into management, Song used the early hours to prepare for high-level client meetings: “I would knock the socks off clients at a 9 am meeting because I always felt so well prepared.”

Yet these success stories are still the exception. Most management experts say that working late is more readily acknowledged and rewarded than working early. Research conducted by Adrian Gostick and Chester Elton, human resources consultants, showed that “the No. 1 reason people are recognised on the job is extra effort, and typically, it’s being recognised for longer and later hours, rather than earlier,” Gostick said. He and Elton surveyed 200,000 managers and employees nationwide from 1996 to 2006 for their book The Carrot Principle: How the Best Managers Use Recognition to Engage Their People, Retain Talent, and Accelerate Performance. The Jackson Organization, a market research group, financed the study.

If you prefer working extra hours early in the morning, ensure that the time is acknowledged by making your presence known. If your manager is not in when you are, send e-mail or leave voice mail that is date — and time — stamped, said Francie Dalton, a workplace behaviour expert and president of Dalton Alliances in Columbia, Maryland.

“If you want to move up the ladder, you have to make yourself visible,” Dalton said. As often as you can, “put something of value on the boss’s desk, so he sees it as soon as he gets in,” she said.

Discuss your early hours with your manager, said Brody, the executive coach, and ask if there are specific tasks you can tackle during that time.

But if you are an early bird struggling to fit into a night-owl culture, it may be time to switch to a company — or an industry — that values early workers, said Roberta Chinsky Matuson, a consultant at Human Resource Solutions in Northampton, Massachusetts. “Industries like the airlines, hotels, 24-hour data centres, health care providers and global financial companies are places where those early-morning hours are valued,” Matuson said.