There should not be a separation between the two.
It is well known that the prophet Muhammad and his first wife were merchants. Abu Bakr as-Siddik was not only a prominent businessman, he was also one of the wealthiest in his tribe at one point, and a well-known philantropist. In fact, he earned a lot of respect from his opponents at the time because he had earlier donated a lot of wealth to help many of them. Many other early Muslims were incredibly wealthy, but spent much of that wealth furthering the cause of Islam.
In general, people will respect the world more than the afterlife. I recall a hadith where one of the Prophet's Companions said that people only work so hard for the world because it is what they can see. If they could see what was in the afterlife, they would rush for that first.
Being successful in life gains you some respect. Turning down some of the luxuries of life in order to serve Allah will give you and your religion far more respect. The earliest Caliphs chose to live as the poorer citizens of their countries, despite being some of the most powerful people in the world at the time. This earned them a lot of respect.
I was taught that work is a fard kifayah - someone in the community has to do it. Without engineers, who will have buildings? Much of the disrespect for Islam today comes from how Muslim nations are technologically and socially backwards. The golden ages of Islam was when they were technologically and socially at the peak of the world.
Being successful in life is a form of da'wah. Converts to Islam do not look at the hermits or listen to the clerics. They watch the regular people who are practicing Islam. If a person can maintain a good career-religion balance, it becomes an impressive feat.
Look to the times of the Rightly Guided Caliphs - a potential governor and military leader is expected to be able to lead people in Friday prayers. They were also strongly career people, considering the degree of success they had in modernizing Arab cities at the time, but they were also religiously passionate.